The correct answer is 45.
A dihybrid cross is a mating experiment between two organisms that are identically hybrid for two traits.
In F1 generation all of the offspring will be heterozygous. In F2 generation the phenotype ratio will be 9:3:3:1. 9 represents the ratio for dominant phenotype.
If there is 80 individuals than:
80/(9+3+3+1)=5
5*9=45
