In Studying a Species of Fish, a Structure Is Discovered

In studying a species of fish, a structure is discovered that has no apparent function. If this is a vestigial structure, what would you find in at least some relatives of this fish?

A) The structure should be absent.
B) A similar structure should be present, but it would be larger and have a function.
C) The structure should look different and also have no function.
D) The structure should be absent from fossils of ancestors of this species.