Final answer:
The estimated time for the last common ancestor to all living primates is 50 million years ago.
Step-by-step explanation:
According to mtDNA predictions, the estimated time for the last common ancestor to all living primates is 50 million years ago (c). By analyzing the mutational relationships in mtDNA, researchers have determined that all humans can trace their ancestry back to one female who lived in Africa about 200,000 years ago through matrilineal descent. This supports the timeline of genetic divergence estimated by analyzing mtDNA and the Y chromosome.