Why Can't Any Star, No Matter How Massive, Fuse Elements

Multiple Choice

Why can't any star, no matter how massive, fuse elements heavier than iron?

A) Because the nucleons within iron have the least mass possible
B) Because elements heavier than iron have less average mass per nucleon
C) It could happen, we just have not yet observed a star massive enough to do this.
D) Actually, this occurs on a regular basis, which explains the great abundance of heavy elements.