Answer:
Use Variance
Step-by-step explanation:
Damien and Sandy have been used the use variance. Because the existing zone only allowed the single-family there. The duplex has to be represen other than to be the originally intended to be used.
Thus here when Sandy and Damien used condemned house. They have been tore it and make a duplex. They live at one side self and rented another part of a duplex. Later on, the area has been zoned for a single-family. So that they have to grant for a use variance.