TASK DEFINITION: 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").
PROBLEM: A tone is made when a hammer makes contact with (A) a waterfall (B) air (C) an solid object (D) a log

SOLUTION: C

PROBLEM: Which can be used to pass information from one person to another? (A) an invention by Marconi (B) an invention by Newton (C) an invention by McCormick (D) an invention by Pasteur

SOLUTION: A

PROBLEM: Which activity would most increase atmospheric CO2? (A) gardening (B) walking (C) speedboat driving (D) planting trees

SOLUTION:
C