Answer:
A. Recessive
Explanation:
Only answers A and C can be used to describe an allele, so B and D can't be it. If the allele was dominant, only one copy would be necessary for the phenotype to be expressed (ex. heterzygous green peas are still green, even though they carry a yellow allele). Therefore, since 2 copies are present for this phenotype, it must be recessive.