Humans Share Several Features with Salamanders

Humans share several features with salamanders. Certain genes and proteins are nearly identical between the two species; both species have four limbs with a similar skeletal structure; the species' early embryos are similar; and where the salamander has a functional tail, humans have a vestigial tailbone. In evolutionary terms, these are examples of

A) geographic similarity.
B) homology.
C) adaptation by natural selection.
D) artificial selection.