Ared bull is crossed with a white cow and all of the offspring are roan, an intermediate color that is caused by the presence of both red and white hairs. this is an example of alleles that are

The intermediate color or rather condition, in this case "roan", is a result of two alleles being codominant. Codominance occurs when the phenotype (or the physical expression of the gene) of a heterozygote individual expresses both the alleles in a pair of genes. In the given situation, both parents are homozygotes. 

The answer is a. i hope this

A