Aquinas's Third Way to Prove the Existence of God Relies

Aquinas's third way to prove the existence of God relies on the claim that

A) There cannot be an infinite causal series.
B) There cannot be something that is better or worse without something that is perfectly good.
C) There cannot be contingent things without a necessary thing.
D) There cannot be unintelligent things that aim at ends without an intelligent designer.