Two six-sided number cubes are rolled. each number cube has sides numbered 1 through 6. what is the probability that the outcome of the roll is an even sum or a sum that is a multiple of 3?

This is the concept of probability and statistics, we are required to find the probability that when a 6-sided cube is rolled the outcome will be even sum or a sum that is multiple of 3.
The probability space is:
x=(1,2,3,4,5,6)
P(x)=1/6
P(even)=3/6=1/2
P(multiple of 3)=3/6=1/2
P(even or Multiple of 3)=1/2*1/2=1/4

Ithink is a. true, but not sure