Mitochondrial DNA Is Useful for Tracing Ancestry Because

Mitochondrial DNA is useful for tracing ancestry because:

A) recombination rarely occurs.
B) mutations in mitochondrial DNA are rare; mitochondrial DNA has relatively little variation.
C) mutations in mitochondrial DNA are almost always harmful.
D) both recombination and mutation in mitochondrial DNA are rare.
E) both recombination and mutation in mitochondrial DNA are rare, but when mutations do occur, they are almost always harmful.