Mitochondrial dna accumulates dna mutations quickly. because of this, it would be most beneficial in analyzing the ancestral relationship of organisms that are a. mitochondrial dna is beneficial in both of these cases b. mitochondrial dna is not used to analyze relationships c. closely related d. distantly related

The answer would be: A. Mitochondrial DNA is beneficial in both of these cases

Mitochondrial DNA or mtDNA is DNA that found in the mitochondrial. Mitochondrial DNA only inherited from mother, so it's relatively unchanged than nuclear DNA that mixed from father and mother. 
Mitochondrial DNA has higher mutation rate in animals because it doesn't have repair mechanism like nuclear DNA. These mutations can be used as a clue for how close the relation of an organism to others.
This makes analyzing the ancestral relationship of organisms that closely or distantly related easier.

The right answer is c.sandstone.