In an R-2 District and subject to the requirements of that district except as herein provided, the following regulations shall apply to professional and financial services (physician, dentist, architect, engineer, attorney, real estate, insurance agent or similar profession):
A. There shall be no exterior evidence, other than a permitted sign not exceeding two square feet, to indicate that the building is being used for any purpose other than that of a dwelling.
B. There shall be no show window or display window.
C. Only two persons other than the professional may be employed.
D. Sufficient off-street parking in the side or rear yard must be provided, with five spaces being the minimum.