The Optimal Relaxed Solution for an ILP Has X₁ = $\ge$

Multiple Choice

The optimal relaxed solution for an ILP has X₁ = 3.6 and X₂ = 2.9. If we branch on X₁, what constraints must be added to the two resulting LP problems?

A) X₁ $\ge$ 3, X₁ $\ge$ 4
B) X₁ = 4
C) 3 $\le$ X₁, X₁ $\le$ 4
D) X₁ $\le$ 3, X₁ $\ge$ 4