Show how to approximate the required work in joules by a Riemann sum. Let x be the height in meters below the top of the tank. Enter xi as xi. What is the limit as n approaches infinity of the sum from i=1 to n of x times Delta x?

A) The Riemann sum is used to approximate the work in joules.
B) The Riemann sum is used to calculate the height of the tank.
C) The Riemann sum is used to determine the volume of the tank.
D) The Riemann sum is used to find the surface area of the tank.