Suppose the landlord really wants the back door to be installed. For too long he has had to cut through the garage and he figures when he retires, this house will be a perfect downsize home for him to move into

How should the constraint for the back door be written if he uses the following scheme for decision variables?

x1 = contractor works on wood floors x2 = landlord works on wood floors
x3 = contractor works on kitchen tile x4 = contractor works on kitchen tile
x5 = contractor works on back door x6 = contractor works on back door
x7 = contractor works on garage door x8 = contractor works on garage door

A) x5 + x6 ? 1
B) x5 + x6 = 1
C) x5 - x6 ? 1
D) x5 - x6 = 1

Answer: B