How would one explain a testcross involving F1 dihybrid flies in which more parental-type offspring than recombinant-type offspring are produced?a. Both of the characters are controlled by more than one gene.b. The two genes are linked but on different chromosomes.c. Recombination did not occur in the cell during meiosis.d. The two genes are closely linked on the same chromosome.

Sometimes, it happens that two genes for different traits are located very close on the same chromosome. The spacing between the two genes is so less that during crossing over in meiosis, these genes do not get separated. Hence, these genes will be inherited together in the offsprings as they do not get separated.

This phenomenon explains why there will be more parental type flies than the recombinant type flies in the dihybrid cross.