Who Was "Mitochondrial Eve" and How Does She Support the Out-Of-Africa

Who was "mitochondrial Eve" and how does she support the out-of-Africa hypothesis?

A) She is the nuclear DNA ancestor of all living humans; her origins trace back to Africa, indicating an African origin for modern humans and supporting the out-of-Africa hypothesis.
B) She is the mtDNA coalescent of living humans; the timing of coalescence indicates greater mitochondrial diversity in the rest of the world as compared to Africa, supporting an African origin for modern humans as genetic diversity increases over time.
C) She is the mtDNA coalescent of living humans; the timing of coalescence indicates greater mitochondrial diversity in Africa than the rest of the world, supporting an African origin for modern humans.
D) She is the nuclear DNA coalescent of the hominoids; the timing of coalescence indicates an earlier split between modern humans and chimpanzees with greater genetic diversity in Africa than the rest of the world, supporting the out-of-Africa hypothesis.