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").

[EX Q]: We can calculate a speed if we know a number of (A) gallons (B) millimeters (C) dollars (D) pounds
[EX A]: B

[EX Q]: Someday, the ground under the pile of rotting grain in the field will be (A) barren (B) a hole (C) more fertile (D) less fertile
[EX A]: C

[EX Q]: Increasing the amount of heat can be done by (A) adding gas to a fire (B) putting a pot on the stove (C) covering up with a blanket (D) moving to a warm climate
[EX A]:
A