(a) No building or structure shall be located, erected, constructed, reconstructed, enlarged or structurally altered except in conformity with the area, height and yard regulations of the district in which such building or structure is located.
(b) No building, structure or lot shall be used for any purpose other than that which is permitted in the district in which such building, structure or lot is located.
(c) No yard or other open space existing about any building or structure shall be so reduced in area or dimension as to make it less than the minimum required by this Zoning Ordinance.
(d) No lot held under one ownership at the time of the effective date of this Zoning Ordinance (Ordinance 14, 1967, passed May 22, 1967) shall be reduced or subdivided in any manner below the minimum area and yard provision required by this Zoning Ordinance.