问题详情

A bag contains 3 red, 4 white, and 5 blue marbles. Jason begins removing marbles from the bag at random, one at a time. What is the least number of marbles he must remove to be sure that he has at least one of each color？
A．3
B．6
C．8
D．10
E．12请帮忙给出正确答案和分析，谢谢！