In Humans, Straight Thumbs Are Caused by the Dominant Allele

Multiple Choice

In humans, straight thumbs are caused by the dominant allele T, while individuals who are tt have thumbs that curve backward ("hitchhiker's thumb") . Consider a family in which the father has straight thumbs, and both the mother and their only child have curved thumbs. What is the chance that their next child will have curved thumbs?

A) 25%
B) 50%
C) 75%
D) 100%