Answer:
{e}, {m}, {w}, {e,m}, {e,w}, {m,w}, {e,m,w}
The answer is k=4 you're welcome
18 (goes down): 17, 16, 15
12 (goes up): 13, 14, 15
The shortest height at which the two stacks of boxes will be the same height is 15.
Hope I was able to help!
The third option should be correct
