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?I?) .Seventy five individuals are homozygous for the trait (I?I?) .Everyone else is heterozygous (I?I?) for the trait.What is the frequency of allele A 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