A Company Makes Two Products, X₁ and X₂ $\ge$ 20, X₂ $\ge$

Multiple Choice

A company makes two products, X₁ and X₂. They require at least 20 of each be produced. Which set of lower bound constraints reflect this requirement?

A) X₁ $\ge$ 20, X₂ $\ge$ 20
B) X₁ + X₂ $\ge$ 20
C) X₁ + X₂ $\ge$ 40
D) X₁ $\ge$ 20, X₂ $\ge$ 20, X₁ + X₂ $\le$ 40