Answer:
A. 16
Explanation:
We have to find rate of change of function from x=3 to x=5 
The average rate of change for the interval a≤x≤b is given by: 
Rate of change= (f(b)-f(a))/(b-a) 
In our question, 
a=3 
and 
b=5 
We can see from the table that at x = 3, the value of function is 18 
So, 
f(a)=18 
and 
At x=5, the value of function is 50 
f(b)=50 
Rate of change=(50-18)/(5-3) 
=32/2 
=16 
So the rate of change of function between x=3 and x=5 is 16 .. 
Option A is the correct answer..