ANSWER
A. 27.5
Step-by-step explanation
The average rate of change of the given quadratic function on the interval;
x=2 to x=4 is the slope of the secant line connecting the points (2,f(2)) and (4,f(4)).
This implies that the average rate of change is

From the table,

and
f(2)=9.
The average rate of change becomes


The correct choice is A.