Co dominance Biology help (Mendelian Genetic)

Question is:

The gene for pea comb (P) in chickens is dominant to the gene for single comb (p), but the genes for black (B) and white (B') feather show co dominance, BB' individuals having blue feathers. If birds heterozygous for both pairs of genes are mated, what proportion of offspring should be:

a. Single-combed?
b. blue-feathered?
c.white-feathered?
d. white feathered, pea combed?
e. blue-feathered, single combed?

Please help/teach me on how to do this question; I will be awarding 10 points whoever cna help me with this question!

A. single combed - 1/4 25%
b. Blue feathered - 1/2 50%
c. white feathered - 1/4 25%
d. white feathered/pea combed- 18.75%
e. blue feathered/single combed- 12.5%

Okay this might be a long answer but i think if you read the whole thing youll understand it better. First lets take the key things from this problem, P (pea comb) is dominant over p (single combed). B(black) ill refer to B' as b so b is white, it also states that Bb is blue. One of the most important things we can see is HETEROZYGOUS meaning that each bird has the genes PpBb so we know that every problem relates to PpBbXPpBb. Ill do what i believe to be the easiest approach to this problem, what we can do now is cross the two genes separately it should look like this

P___p B_____b
P|PP|Pp B BB | Bb
p|Pp|pp b Bb | bb

Genotype Phenotype Geno.
1PP 3P 1BB
2 Pp 1P 2 Bb
1 pp 1 bb