A building or premises shall be used for the following purposes:
A. Any use permitted in the "A" or "B" districts;
B. Advertising signs and billboards not exceeding forty square feet in area when attached to a building and not extending more than one foot from the surface of the building pertaining to the character, type, ownership or occupancy of the building or its contents;
C. Amusement place or theaters; provided, however, that no theater shall be erected or reconstructed unless there is provided on the same lot, or within three hundred feet thereof, a space for off-street parking which contains an area adequate to accommodate one automobile for every five seats in the theater;
D. Trailer and tourist camps or courts; provided, however, that all yard and interior court regulations of the "B" multiple dwelling district are complied with; and provided further, that there shall be no more than one trailer or one tourist camp unit for each one thousand square feet of lot area. Any building used primarily for any of the above enumerated purposes may have not more than forty percent of the floor area devoted to industry or storage purposes incidental to such primary use; provided, that not more than ten employees shall be engaged at any time on the premises in any such incidental use. (Prior code § 11-3-3 (b)(1-4))