Task: Question Answering
Input (English): There are a total of 20 marbles in a bag containing only red marbles, blue marbles, and yellow marbles. If a marble is selected at random, the probability of getting a red marble is \(\frac{2}{5}\) and the probability of getting a blue marble is \(\frac{1}{2}\). How many yellow marbles are in the bag?
(A)1 (B)2 (C)4 (D)8 (E)10
Output (English): B