To investigate whether roots exert a pushing force strong enough to cause water to move up the stems plants, my question is explain two reasons why we can conclude thatthe rise of water in this glass tube is due to root pressure and not transpiration and capacity

The stem of the plant should be cut at least three to four inches above the surface level.
The glass capillary should be tightly fixed with the stem.
The initial water level and the final water level should be carefully noted.
The droplets on the leaves should be observed and conclude that these drops are not from transpiration. 

Ithink the answer is d.