BROCK, Judge.

Defendants’ answer and evidence at trial, and the thrust of their arguments on this appeal, are centered upon their contention that plaintiffs had cancelled the option to purchase the tract of land by subsequent oral agreement.

*608 Defendants bring forward eight assignments of error, but in their brief they abandoned three of these — numbers 1, 6 and 8.

In defendants’ second and third arguments (assignments of error numbers 2 and 3 respectively), they contend that the trial judge committed error when he instructed the jury that the issue was whether this option agreement was cancelled by the subsequent oral agreement. Defendants maintain that they did not receive the full benefit of law in the charge in that an option could be cancelled when the prospective purchaser waived said option by conduct which naturally and justly lead the other party to believe that the option provisions have been waived.

In the absence of a definite parol recision or abandonment of rights under an option contract, an abandonment or waiver of such rights is to be inferred only from positive and unequivocal acts and conduct which are clearly inconsistent with the contract. Bell v. Brown, 227 N.C. 319, 42 S.E. 2d 92. In our opinion, there is no evidence in this case of acts or conduct by plaintiffs which would justify the jury in finding that plaintiffs had positively and unequivocally acted inconsistent with the contract. Therefore, no instruction by the judge upon this principle of law was required.

We note also that defendants’ pleading and the issue submitted to the jury referred only to an oral cancellation. The issue was as follows:

“Was the option agreement marked Court’s Exhibit # 1 cancelled by subsequent oral agreement as alleged in the defendants’ answer?”

Defendants lodged no objection to the issue as submitted and they did not tender other issue; therefore, no question of abandonment or waiver by conduct was required to be presented. These assignments of error are overruled.

Defendants’ argument number four is an interesting recommendation for expository speaking, but we do not agree that the instruction complained of was misleading. In our opinion, there is no reasonable cause to believe that the jury was misled or misinformed on the burden of proof.

Defendants’ final argument (assignments of error numbers 5 and 7) is based on the contention that Allen L. Hayes *609 was the agent of his wife. They argue that the trial judge should not have left the jury free to determine whether the husband was acting as agent for the wife. In effect, the defendants contend that the judge should have peremptorily instructed the jury that the husband was the agent for the wife.

No presumption that the husband is acting as agent for the wife arises from the mere fact of the marital relationship, Sheppard v. Andrews, 7 N.C. App. 517, 173 S.E. 2d 67, but rather there must be proof of the agency. Beaver v. Ledbetter, 269 N.C. 142, 152 S.E. 2d 165. The evidence in this case would justify, but does not impel the jury to find that Allen L. Hayes was acting as agent for his wife.

Defendants rely upon the holding in Dobias v. White, 240 N.C. 680, 83 S.E. 2d 785, to support their contention that the court should declare as a matter of law that Allen L. Hayes was acting as agent for his wife. We do not interpret Dobias as supporting defendants’ argument. In the first place, the facts in Dobias are so substantially different from those of the instant case that the two cases are distinguishable on the facts alone. In the second place, the language in Dobias relied upon by defendants is simply obiter dictum. Appellants in Dobias abandoned their assignment of error relative to a finding of agency by the trial court; therefore, no discussion of the agency question was necessary to a decision in the case. In the third place, in Dobias the parties waived trial by jury and the trial judge was acting as a “finder of facts” when he found that the husband was acting as agent for the wife. He did not rule as a matter of law. In the instant case, the trial judge submitted the question to the jury for it to find the facts from the evidence. In doing so he did not commit error.

No error.

Judges Hedrick and Vaughn concur.