Butterflies can produce hundreds of offspring per cross. In a certain variety of butterflies, a maternally-imprintable gene is responsible for wing phenotype. Two possible alleles for this gene are w for normal wings and wc for crinkled wings. Which of the following pieces of information would be helpful in predicting the wing phenotype of a male offspring from a cross? a. look at the father's phenotype
b. know the mother's genotype
c. look at the mother's phenotype
d. know the father's genotype

The option that would be helpful in predicting the wing phenotype of a male offspring from such a cross would be to look at the father's phenotype.

Imprinted genes can simply be defined as genes that are expressed in parent-of-origin specific manner and result from a chemical modification of DNAs.  Such genes are differentially expressed depending on which of the two parents they are inherited from. Hence:

Phenotype refers to the physical appearance or expression of a gene. Therefore, if a gene is maternally imprintable, looking at the phenotype of the father would be helpful in predicting the phenotype of the male child in case a cross happens.

Applying the same principle to the butterfly, it will, therefore, be helpful to look at the father's phenotype in order to predict the wing phenotype of a male offspring from a cross.

The correct option is A.

More about imprinted genes can be found here:

answer; both surfaces of the membrane are nonpermeable