Genes Usually Have Multiple Alleles

Multiple Choice

Genes usually have multiple alleles. Alleles that have the same phenotype can be grouped together. Alleles can also be ranked in an allelic series, such as with agouti, which governs coat color in dogs and other animals. Rank the following alleles for the hypothetical gene C, governing hair color, in order of dominance (most dominant first) .
There are four alleles: C^r, C^y, C^b, and C^w. Individuals homozygous for these alleles have red, yellow, black, and brown hair, respectively. C^r_ individuals have red hair. Heterozygotes carrying C^y do not have yellow hair. In a cross between homozygous C^b and C^w individuals, ¾ of the offspring have brown hair.
-(most dominant) = C^r

A) 1 (most dominant)
B) 2
C) 3
D) 4 (least dominant)