What is the likelihood of your sharing an allele with a parent or with a sibling? a. The chance that you share an allele with either a parent or a sibling is one fourth. b. The chance that you share an allele with a parent is one-half and with a sibling one fourth. c. The chance that you share an allele with a parent is one-fourth and with a sibling one eighth. d. The chance that you share an allele with either a parent or a sibling is one half.

Option D, The chance that you share an allele with either a parent or a sibling is one half.

Explanation:

All  individuals receive 50 percent of their genes from each parent, Thus,  it can be said that each sibling will share nearly half of their genetic material with each parent. In case of full siblings (when both the parents are same), 50 percent of their genetic material matches.  

For instance,

There are two parents each with genotype  AA and aa

Cross between AA and aa will produce following offspring

AA * aa

Aa, Aa, Aa, Aa

Thus, each offspring will have one gene from each parent and hence they share 50% of their genetic material with their parents

Two siblings get the same gene from their two parents. Hence, 50 percent of their genetic material matches.  

Hence, option D is correct