One-Hundred Guests During a University's Parent Day Are Asked Who

One-hundred guests during a university's Parent Day are asked who it is they are visiting while they're on campus. Thirty indicate that they are visiting their son, forty indicate they are visiting their daughter, twenty indicate that they are visiting a grandchild, and ten indicate that they are visiting two children. What is the relative frequency for guests who are visiting their daughter?

A) .10
B) .20
C) .30
D) .40
E) .50