You roll a red die and a green die. what is the size of the sample space of all possible outcomes of rolling these two dice, given that the red die shows an even number?

(red, green) = (2, 1), (2, 2), (2, 3), (2, 4), (2, 5), (2, 6), (4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (4, 6), (6, 1), (6, 2), (6, 3), (6, 4), (6, 5), (6, 6)
Size of sample space = 18.

Letter c i’d say