I believe the answer is C. It doesn't make sense to drop an object from -16 feet, and it doesn't make sense to have a -120 in the equation. It should be positive for it to come out right.
The correct answer is definitely C. Note how the highest off the ground that the object will ever be is 120 ft, and that the -16*t^2 term clearly demonstrates that the object is falling from height 120 ft. That -16 comes from g, the acceleration due to gravity, which is -32 ft per (second squared).
