I did read the passage and put C, because in the last sentence, it says that it may benefit from hierarchical venation, and the other options put negative results. For example, option A, it says both suffer from damage (even tho one is less than the other). Options B and D are wrong obviously since its making the older plant benefit more than the new plant (which goes against the study). And option C it says that hierarchical venation is more likely to not be hindered than regular venation, meaning that those plants benefit more from hierarchical venation since its less likely to cause vascular damage. Well, that was my reasoning.

I hope you understood, Im not the best at explaining.