In Certain Latin American Countries During Periods of Political Volatility

In certain Latin American countries during periods of political volatility, children were removed from their families and their parents were executed (then referred to as being "disappeared") . The methods with the best chance of reuniting those children with members of their extended family have used mtDNA matching. Why and how?

A) Children's mitochondria will have genomes that are 1/4 identical to each of their grandparents.
B) Children's mitochondria will have genomes that are 1/2 identical to their maternal grandparents.
C) Children's mtDNA will be identical to those of their first cousins.
D) Remains of the children's mothers can be used to match their mtDNA with that of their children.
E) Children's mitochondria will have genomes that are identical to those of their maternal grandmothers.