Final answer:
The genotypes of both homozygous black guinea pig parents are BB, so the correct answer is B) BB and BB.
Step-by-step explanation:
The question you've asked is related to genetics, specifically Mendelian inheritance in guinea pigs. If a homozygous black guinea pig is mated with another homozygous black pig, the genotypes of the parents would both be BB. Black coat color is dominant, which is represented by the letter B, and since both parents are homozygous, they each contribute a dominant allele.
Therefore, the correct answer to your question is B) BB and BB.