how to solve

If the function f(x) represents the height of a steep hill and you wish to estimate the slope at a particular point using simple tools, which method would be most effective according to calculus principles? Choose only ONE best answer. A Use aruler and string to measure angles and slopes directly =} Apply the concept of average slope over a small interval Use the derivative of the function at the point for an accurate measurement D Approximate using the difference between two far-apart points on the hill