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. -22.7 feet B. -16.7 feet C. -11.7 feet D. -9.7 feet