Which of these conditions made it beneficial for aquatic plants to move onto land?

Not knowing what the choice of conditions is, I would say that it would be very damp conditions on land, and if the plant photosynthesises it would be good because of 'purer' sunlight. but if show what the choice of conditions are I can give you a more accurate answer (hopefully)

Sunshine, and damper areas. If it's aquatic it probably lives in water, so have damp swampy ground could help.

Volcanoes make new rocks so not ahotspots are the the stuff that makes volcanoes mid atlantic ridge(mar cause i’m lazy) is a constructive plate boundary so it makes sense that new rocks would be found near it, also the mar is in the middle of the ocean so it fits the description deep ocean trench, umm, there’s no ocean trenches to where you’re goingso the mar is most likely the answeri wouldn’t trust me but hey why not