The mode of a set of numbers is the number that appears more times in the set.
So to find the mode of this set, let's check how many times each number appears:
number 1: 2 times
number 2: 3 times
number 5: 2 times
number 8: 1 time
number 9: 1 time
number 10: 1 time
number 11: 1 time
So we can see that the number that is repeated more times is the number 2 (it appears 3 times).
Correct answer: (A)