Answer:
The most likely genotypes for the two blue budgies would be yyBb
Step-by-step explanation:
There are three options to cross two blue parakeets:
yyBB x yyBB
yyBB x yyBb
yyBb x yyBb
of the first option, the F1 genotypes will be 100% yyBB (blue)
In the second option, the F1 budgies will be yyBB or yyBb (blue in both cases). In contrast, in the third option, the F1 genotypes will be yyBB, yyBb (blue in both cases) and yybb (white).