The rate of change of function A is 4
The rate of change of function B is 3 (option D)
Step-by-step explanation:
We are looking for the rate of change of two functions.
m is also known as the rate of change

comparing the equation above to a linear function:
y = mx + b
m = slope , b = y -intercept
For function A:
m = slope = 4, b = 6
To get the rate of change of function B, we need to find the slope of any two points on the table.
For linear function, the slope is constant irrespective of the two points used in calculating it.
Formula for slope:

using points; (1, 3) and (3, 9)

The rate of change of function A is 4
The rate of change of function B is 3 (option D)