In Drosophila,the genes crossveinless-c and Stubble are linked,about 7 map units apart on chromosome 3.cv-c is a recessive mutant allele of crossveinless-c (cv-c+ is wild type),while Sb is a dominant mutant allele of Stubble (Sb+ is wild type). A dihybrid female Drosophila with genotype cv-c Sb+/cv-c+Sb is testcrossed.The proportion of phenotypically wild-type individuals in the progeny of the testcross will be: