If Both Parents Are Carriers of a Recessive Disease Allele

Multiple Choice

If both parents are carriers of a recessive disease allele, what is the chance that one of their unaffected children is also a carrier?

A) the chance that an unaffected child is a carrier is 50%
B) the chance that an unaffected child is a carrier is 2/3
C) the chance that an unaffected child is a carrier is less than 50%
D) the chance that an unaffected child is a carrier is 0%
E) the chance that an unaffected child is a carrier is 75%