which of the following is an example if zoning variance

a- moderate violation of setback requirements is allowed so that an office building is built far enough from a high presuire natural gas pipline

b- modest violation of federal fair housing laws is allowed as a means of controlling population density in a new suburban area

c - a developer is allowed to include the deed restriction that all lots in subdivision contain a houae of at least 3,000 sq ft of living area

d- a developer is allowed to include the deed restrictions that all lots in subdivision must bave a swimming pool built in them