A Company Will Be Able to Obtain a Quantity Discount $\le$

A company will be able to obtain a quantity discount on component parts for its three products, X₁, X₂ and X₃ if it produces beyond certain limits. To get the X₁ discount it must produce more than 50 X₁'s. It must produce more than 60 X₂'s for the X₂ discount and 70 X₃'s for the X₃ discount. Which of the following pair of constraints enforces the quantity discount relationship on X₃?

A) X₃₁ $\le$ M₃Y₃, X₃₂ $\ge$ 50Y₃
B) X₃₁ $\le$ M₃Y₃, X₃₁ $\ge$ 50
C) X₃₂ $\ge$ (1/50) X₃₁, X₃₁ $\le$ 50
D) X₃₂ $\le$ M₃Y₃, X₃₁ $\ge$ 50Y₃