My vote would be b. because generally when we are figuring area of a room, we are working with materials that are not exact and we usually round off .75 to the next foot. (I have experience in flooring!)
I am sure there are situations where you would want it to be exact however, such as using VERY expensive materials to cover.
Do you want the exact form or decimal form?
Slope is -3 and y intercept is 2