DEC 1992, LR 2, #14 (Please help me understand why this is the correct answer)

LSAT Determined

Hello,

I don't understand why D is correct. I chose B. Could someone please explain why the right answer is right and the wrong answers are wrong? Thank you in advance.

deleted account

They are giving a counterexample to the government's claim in D. The government says that since GLOBAL atmospheric ozone levels remained constant, the ozone layer over the Arctic must be fine. The counterexample is that the ozone layer over the Arctic is not fine, because the ozone is moving. Given that, GLOBAL can stay constant, but local may change.

Please excuse the caps. Using for emphasis, not yelling haha.