The Individual with Genotype AaBbCCDdEE Can Make Many Kinds of Gametes

The individual with genotype AaBbCCDdEE can make many kinds of gametes. Which of the following is the major reason?

A) segregation of maternal and paternal alleles
B) recurrent mutations forming new alleles
C) crossing over during prophase I
D) different possible assortment of chromosomes into gametes
E) the tendency for dominant alleles to segregate together