WW or ww WW or Ww WW only Ww only
I gave my students this multiple choice question: A "widow's peak" hairline in humans is coded by the dominant allele W. A straight hairline is coded by the recessive allele w. A man with a homozygous dominant WW produces a zygote with a woman with a heterozygous dominant Ww for the trait. Which allele combinations could occur in the zygote?

Only one answer is correct among these 4 choices:
- WW or ww
- WW or Ww
- WW only
- Ww only

Could you tell me which one is correct?

WW or Ww