B is correct, "<span> Christina and I went to the same summer camp for years (since we were 8)" </span>parentheses are used when you have some extra information you want to add, but its not completely necessary. Like how they started going to the same summer camp when they were 8, you can still read the sentence fine without it, but it's a nice piece of information.
<span>B."Given this, a parent might be tempted to give up trying to make good decisions and simply let the chips fall where they may."
This is the counterclaim, but the author continues to show how it's not a good idea to completely go the other way, that children will notice if their parents give up and might think they don't care about their future.</span>
The passage saying the earth is round is Isaiah 40:22:
He sits enthroned above the circle of the earth, and its people are like grasshoppers. He stretches out the heavens like a canopy, and spreads them out like a tent to live in.
