GRE Official Guide, Test 1 Section 6, 3,8.

I am quite puzzled about how this answer is A. I answered B, as the greatest Line that can go through point A is AB, the diameter.

In the question below, if you solve for x, the ans is -1/+1 which is less/greater than -.05, so the answer I gave was D, but the answer given is B.

Any explanation would be helpful.