In this task, you are given a multiple-choice question and you have to pick the correct option. Answer with option indexes (i.e., "A", "B", "C", and "D").

Northern countries have extensive erosion due to (A) glacial liquification (B) cola mining (C) more frequent tornadoes (D) meteors
A

When cutting down rain forests, it is important to keep in mind air quality. When too many trees are cut down in a given area, there may be decrease in the air's (A) quality (B) carbon dioxide (C) helium amounts (D) carbin dioyide levels
A

The moon is absent of (A) craters (B) gravity (C) H2O (D) CO2

C