TASK DEFINITION: You are given a science question (hard-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.
PROBLEM: Greta passed a comb through her hair several times. She then placed the comb next to a stream of water flowing from a faucet. Greta observed the stream of water bend toward the comb. How did passing a comb through her hair allow the comb to bend the stream of water?
(A) by making the comb more absorbent (B) by giving the comb an electrical charge (C) by increasing the thermal energy of the comb (D) by breaking some of the chemical bonds in the comb

SOLUTION: B

PROBLEM: While collecting wildflowers, a student begins to sneeze and has itchy, watery eyes. What bodily system causes this reaction?
(A) immune (B) nervous (C) muscular (D) circulatory

SOLUTION: A

PROBLEM: A solution of water and a nontoxic compound is produced in science class. What should be done with the solution when the demonstration is complete?
(A) It should be poured down a drain. (B) It should be poured into a recycling bin. (C) It should be poured into a waste container. (D) It should be placed in a hazardous materials disposal container.

SOLUTION:
C