There Are 300 Individuals in Sample Group #1 Taken from Population

Multiple Choice

There are 300 individuals in sample group #1 taken from population X.Seventy-five individuals of sample group are homozygous for the trait in question (I^AI^A) .Seventy five individuals are homozygous for the trait (I^BI^B) .Everyone else is heterozygous (I^AI^B) for the trait.What is the frequency of allele B in the sample group,assuming the trait is controlled by a single gene?

A) 0
B) 0.375
C) 0.5
D) 0.75
E) 1