What is the difference between a theorem and a proof?

A. A proof is a true mathematical
statement, while a theorem is a
speculation.

B. There is no difference; theorems
and proofs are the same thing.

C. A proof is a mathematical fact,
while a theorem is a series of steps showing why the proof is true.

D. A theorem is a statement of
mathematical truth, while a proof is the series of statements that support the theorem's claim