The answer is B.25
Because if the height is never changed most likely it would be 5 also, so therefore 5 x 5 =25 so the would be the answer
Hope this helps
B. One solution (I think)
It looks like the limit you want to compute is
Since , this limit corresponds exactly to the derivative of at . Recall that
By the chain rule,
Since exists, is differentiable at so it must be continuous.