The inequality is a > 12, which means a is greater than 12. This means that we are looking for numbers that are greater than 12 to place into the solution set. Options A and B are incorrect because 10 and 11 are both numbers less than 12, respectively. Option D is also incorrect because the inequality specifies that the numbers in the solution must be greater than 12, not equal to it, so 12 is not a solution.
This leaves option C as the correct answer, because all of the solutions in the set (13, 14, and 15) are greater than 12.
Therefore, your answer is C.
Hope this helps!