An objection to an individual grand juror may be based on the cause that the grand juror:

1. (1) is less than 18 years of age;
2. (2) is not a citizen of the United States;
3. (3) has not resided in this state 30 days;
4. (4) lacks mental capacity;
5. (5) is a prosecutor upon a charge against the defendant;
6. (6) is a witness on the part of the prosecution, and has been served with process or bound by recognizance as such; or
7. (7) is of a state of mind in reference to the case or to either party which shall satisfy the court, in the exercise of a sound discretion, that the juror cannot act impartially and without prejudice to the substantial rights of the party objecting.