In fruit flies, the recessive pr and cn mutations cause brown and bright-red eyes, respectively (wild-type flies have brick-red eyes). The double mutant pr-cn combination has orange eyes. An F1 female who is wild-type is crossed to an orange-eyed male. Their F2 progeny have the following distributions: Phenotype Observed

Wild-type 8
Brown 241
Bright-red 239
Orange 12
500

The F1 mother of these progeny (F2) resulted from a cross between two flies from true breeding lines (P generation). What are the genotypes of these two lines?

a. pr cn/prcn and prcn/prcn
b. prtcn/prcn and pr cn /prcn
c. prtan lpr cn and prcn/prcn
d. pren /prcn and pr cn/prcn