Biology q

How is the answer D?

Statement 1 states that the sap contains mainly glucose w/ other assimilates: it actually contains sucrose, as any synthesised glucose is formed into sucrose and the main output of the Calvin Cycle for most generic plants is in fact sucrose (remember that it builds up carbon-based molecules, and in general sucrose is the one of preference)

Statement 2 is true enough, as the companion cells do actively onload sugars/etc.

Statement 3 is total hogwash, at least for most plants.

Statement 4 is true: the sugars reduce the osmotic potential, and water flows in via osmosis down a water potential gradient.