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").

In order for trees to use sunlight they must (A) their roots (B) the light switch (C) CPR (D) respire
D

Rocket engines can lift rockets because (A) of how much fuel they use (B) of how fast they are (C) of the power the hit the ground with (D) of how tall they are
C

A seasonal change may be expressed in (A) birds flapping their wings (B) birds leaving a state (C) cows chewing their cud (D) horses being saddled up

B