(a) Within 15 days after service upon the respondent of the accusation, the respondent may file with the agency a notice of defense. In the notice the respondent may
- (1) request a hearing;
- (2) object to the accusation upon the ground that it does not state acts or omissions upon which the agency may proceed;
- (3) object to the form of the accusation on the ground that it is so indefinite or uncertain that the respondent cannot identify the transaction or prepare a defense;
- (4) admit the accusation in whole or in part;
- (5) present new matter by way of defense.