The correct answer is 5. This is because rate of change of a function or a line is its gradient. As we can see that the line is horizontal then the gradient must be equal to zero too.
On the other hand the equation is written in the form of y = mx + c where m is the gradient or slope and c is the y intercept so the gradient is equal to 5 if we match the places. So it is 5 times greater.
