Fossil evidence shows that giraffes living 1000 years ago had much shorter necks than the giraffes seen today. Which statement best explains this observation?

A) The two groups of giraffes are not related.
B) The two groups of giraffes arose as a result of convergent evolution.
C) The difference in neck length is evidence for homoplastic inheritance.
D) The two groups of giraffes were located in different geographical locations.
E) The giraffes acquired longer necks through the continuing process of natural selection.