A Eukaryotic Diploid Cell from an Organism with the ZZ-ZW

A eukaryotic diploid cell from an organism with the ZZ-ZW sex determination system has two pairs of autosomes and a pair of sex chromosomes, Z and W, shown here. What is the probability of a gamete from this individual that has the following genotype: alleles A and b, chromosome Z?

A) 1/2
B) 1/4
C) 1/6
D) 1/8
E) 1/16