It rained all day, so many people played games. In the ring toss, 4 people won the grand prize, 15 people won the first prize, and 30 people won a consolation prize. How many more people won the first prize than the grand prize?
A. 30 people won a consolation prize.
B. 15 people won first prize.
C. It rained all day, so many people played games.
D. 4 people won the grand prize.