TASK DEFINITION: In this subtask, you will answer a simple science question. Please indicate the correct answer. If you're not sure about the answer, choose the last option "I don't know". Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D', 'E'. The "A"-"D" responses correspond to the answer options mentioned in the input. There is a 5th option "E" which should be used for questions for which you're not sure about the answer (e.g., when the questions do not provide enough information to answer).
PROBLEM: Question: Which object is the best conductor of electricity?  (A) metal fork (B) rubber boot (C) plastic spoon (D) wooden bat?

SOLUTION: A.

PROBLEM: Question: How do plants most commonly break large rocks into smaller pieces?  (A) Plant leaves insulate surrounding rocks from extreme temperatures. (B) Plant roots grow into cracks in rocks. (C) Seeds from plants fall onto rocks and release acidic compounds. (D) Stems of plants surround and squeeze rocks?

SOLUTION: B.

PROBLEM: Question: What is the primary energy source that drives all weather events, including precipitation, hurricanes, and tornados?  (A) the Sun (B) the Moon (C) Earth's gravity (D) Earth's rotatio?

SOLUTION:
A.