What Is the Approximate Volume (In Cubic Yards [Yd³]) of the Material

What is the approximate volume (in cubic yards [yd³]) of the material to be excavated between two cross-sections that are 100 feet apart? Assume that the area of the first cross-section is 216 square feet ( ft²) and the area of the second cross-section is 318 ft².

A) 10 yd³
B) 989 yd³
C) 12,640 yd³
D) 26,700 yd³