A Woman with a Defect on One X Chromosome of the Gene

Multiple Choice

A woman with a defect on one X chromosome of the gene for M cones is married to a man with normal colour vision. Of their daughters, on average:

A) Half will have defective colour vision and half will have normal colour vision, but be carriers of the defective gene
B) All will be carriers
C) Half will be normal and half will be carriers
D) All will have defective colour vision