Joel Lived in a Block with a Mixture of One-Family

Joel lived in a block with a mixture of one-family and two-family homes. He finished the third floor of his home for his family and when his children left home, he rented the space out as two apartments. Six months later, the town enacted a zoning ordinance restricting occupancy of the building to a maximum of two unrelated families. Joel's best argument for waiving the ordinance is:

A) there is not much difference between there being two families and three families in the building.
B) he cannot meet the costs of maintaining the building unless he rents both apartments.
C) he is not going to add any more occupants to the building.
D) he was using the third floor as apartments for rent before the zoning ordinance was enacted.