Answer:
a. 11/36 or 33%
Step-by-step explanation:
Possible outcomes in which one of the dice is a 4 are ...
(1, 4), (2, 4), (3, 4), (4, 4), (5, 4), (6, 4), (4, 1), (4, 2), (4, 3), (4, 5), (4, 6)
There are 11 of them, including the case where both dice are 4. Since there are 36 possible outcomes, the probability of one die being 4 is 11/36.
____
The probability of "exactly one" die being a 4 is 10/36 = 5/18, not an answer choice. Hence we assume the above interpretation of the question is the correct one.