Look to the table to find the answer.
The average rate of change is the slope of function taken on the interval [1,3].
The image of the function posted does NOT have a slope of 3 on [1,3] . Looking at the able you see (1,-2) and (3,6) So it has a slope of 4 = (6- -2)/(3-1) on that interval..
Go on to the next function and check the slope for the x interval [1,3] until you find one that is = 3