An Urn Contains 2 Red and 2 Green Marbles

Multiple Choice

An urn contains 2 red and 2 green marbles. We pick a marble, record its color, and replace it. We repeat this procedure a second and a third time. The probability distribution for the number of red marbles is given below.

For this distribution, the probability of exactly one red marble is given by:

A) 1/8.
B) 3/8.
C) 7/8.
D) 1/3.