Phosphorus Trichloride Can Be Made by the Following Reaction: P₄(s)

Phosphorus trichloride can be made by the following reaction: P₄(s) + 6Cl₂(g) → 4PCl₃(l) What is the maximum amount of phosphorus trichloride that can be formed if 15 molecules of P₄ are mixed with 42 molecules of chlorine?

A) 4 molecules
B) 12 molecules
C) 24 molecules
D) 28 molecules
E) 57 molecules