The answer is adenine.
The nitrogenous base pairings are always adenine with thymine and cytosine with guanine.
I remember this as
· the two round letters (C and G) pair together
· the two straight-edged letters (A and T) pair together
Hopefully that helps.
Explanation: All of it is in gamete formation. Meaning, it is going through a gamete formation which also means that pairs of alleles that are for different traits, segregate. They move on independently from one another, never touching.
For your question, It's incomplete dominance which is when cases with one allele isn't complete to be dominant over another allele. It's all got to come together in order for it to become a strong and dominant allele, or else it won't be complete and won't become and do what it has to.
I hope this help you and I hope that I gave you what you wanted/needed for this question.
I believe the answer to your question is c