No further proscriptions or restrictions may be imposed upon employees covered under this regulation except:

1. (a) Employees who are appointed by the President by and with the advice and consent of the Senate;
2. (b) Employees who are appointed by the President;
3. (c) Non-career senior executive service members;
4. (d) Schedule C employees, 5 CFR 213.3301, 213.3302; and
5. (e) Any other employees who serve at the pleasure of the President.