Answer:
100%
Explanation:
A sex-linked trait is a trait which is inherited on the sex chromosomes (X and Y chromosomes). This means that that trait is only inherited by offsprings of a particular sex. In this question, a family is said to have a Y-linked disease that affects the father.
Note that, Y chromosomes are only present in the male sex, meaning that a father will always transfer its Y chromosome to all his male offsprings. Since this disease (trait) is on the Y chromosome, it means that all male offsprings i.e. 100% of this father will have the disease.
