when x = 3, the value of y is y = 4 (row 3 of the table)
when x = 5, the value of y is y = -2 (row 4 of the table)
So we have the two points (3,4) and (5,-2)
To find the average rate of change from x = 3 to x = 5, this is the same as finding the slope of the line through (3,4) and (5,-2)
Slope Formula:
m = (y2 - y1)/(x2 - x1)
m = (-2-4)/(5-3)
m = (-6)/(2)
m = -3
The slope is -3 so the average rate of change is -3
The answer is choice B