If the hair colour in human is controlled by three genes each having two alleles as dominant X, Y and Z and recessive x, y and z contribute quantitatively then which of the following genotypes will show same hair colour?
a. xxYyZZ
b. XXYyZz
d. XxyyZZ
c. XXYyzz
A. a, c and d
B. cand d only
C. band c only
D. a, b and d
