In a BIP Problem,1 Corresponds to a Yes Decision and 0

Multiple Choice

In a BIP problem,1 corresponds to a yes decision and 0 to a no decision.If there are 4 projects under consideration (A,B,C,and D) and at most 2 can be chosen then the following constraint needs to be added to the formulation:

A) A+ B + C + D $\le$ 1.
B) A+ B + C + D $\le$ 2.
C) A+ B + C + D $\le$ 4.
D) A+ B + C + D = 2.
E) None of the above.