The definition of mode is given in different ways.
For example,
Let A = {1,1,2,2,3,3}
As for few references Mode of the set A is given by 1,2,3 i.e., each element is mode, since each element is equally repeated.

But from few other references,
Mode = 3mean - 2 median
so, for set A
mean = 2
median = 2
mode = 2

so, finally which is correct answer.
Mode = 1,2,3
or
mode =2


So, as per GMAT which is correct answer?