How does evidence from embryological studies help support the modern theory of evolution?

How does evidence from embryological studies help support the modern theory of evolution?
 A. Data shows similar structures having different functions reveal a common ancestor.
 B. Studies show closely related organisms will look very similar to one another.
 C. Data reveals a high percentage of genetic similarities between two closely related organisms.
 D. The evidence reveals remnant structures that previously had a function but are no longer needed.