A widow's peak is a point in the middle of the hairline that points down toward the nose. John's parents both have this trait and he does too. Having a widow's peak is a dominant characteristic. Which of the following scenarios would reveal whether John is homozygous or heterozygous for this trait?
1) John has a child with a widow's peak
2) John has a child without a widow's peak
3) John's child has a widow's peak
4) John's child does not have a widow's peak