Answer: The correct answer is- A) They will all be blue.
As per the information given in the question, blue color (B) is dominant trait in butterflies over the yellow color (b), which is a recessive trait.
As we know that dominant trait always masks the expression of recessive trait.
The possible genotypes for blue color butterfly are- Bb (heterozygous dominant) and BB (homozygous dominant) whereas for yellow color butterfly is bb (homozygous recessive).
Genotypes of the parents are - BB (which will produce gametes, B and B) and bb (which will produce gametes, b and b).
When these parents are crossed, their offspring will have the genotype Bb (heterozygous dominant).
Thus, they will all be blue.
