Answer: D.)Carrying a 15 kg object upstairs from the first to the second floor.
Explanation:
Work is simply defined as the ability to move an object a distance, which gives it the formula;
Work= Force × Distance
Force= mass × acceleration
More work is therefore done in lifting the 15kg from the first floor to the second floor, what also adds to the work done is walking with the load through the stair case. Most definitely option D