Can someone please explain why D is wrong? #help

I picked B during the quiz and I stuck with B after my blind review. My understanding is that the water level is higher now than before because water kept dripping down (which formed the stalagmites) then flooded the cave. I think this is the same reasoning explained in the video, just worded differently. Right...?

#help

Is this RC training seminar free?

I thought E was irrelevant when I was doing blind review, but after I listened to JY's explanation, I don't understand why E is wrong anymore... If they're still presuming that teaching children computer skills is worth it, doesn't that counter Parent Q's argument that it's pointless?

C is definitely a better choice, but I thought there's only ever one right answer and no such thing as a "kinda right" answer. I feel like I'm misunderstanding something. #help