At his current level of consumption, Cameron get 3 times more marginal utility from an additional game of pinball than from an additional game of ping pong. If the price of a ping pong game is $0.50, then he is maximizing utility if the price of a pinball game is:
选项：

A:$3.00;
B:$1.50;
C:$2.00;
D:$1.00