Danny has a basement in his house. The elevation of the basement floor is -18.9 feet. A storage cabinet is placed on the basement floor. The top of the storage cabinet has an elevation that is equal to of the approximate elevation of the basement floor. A shelf is placed at a height of 2.5 feet above the storage cabinet.
What is the approximate elevation of the shelf?
A. -9.7 feet
B. -11.7 feet
C. -16.7 feet
D. -22.7 feet