Two Constraints in a Model with Binary Variables Y₁, Y₂ $\le$

Multiple Choice

Two constraints in a model with binary variables Y₁, Y₂, Y₃ representing whether or not project 1, 2, or 3 will be performed are: Y₁ - Y₂ $\le$ 0 and Y₁ - Y₃ $\le$ 0.Taken together, what can be inferred from these constraints?

A) Projects 2 and 3 cannot both be performed.
B) Projects 2 and 3 must be performed if project 1 is performed.
C) Projects 2 and 3 may be performed is project is performed.
D) Project 1 must be performed.