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: When liquid water freezes, it forms ice. What is the physical state of an ice cube?  (A) gas (B) solid (C) liquid (D) plasm?

SOLUTION: B.

PROBLEM: Question: A manufacturer wants to produce a container for food storage that does not break easily and is airtight, inexpensive, and microwave-safe. Which of the following is the best material to use to make the container?  (A) glass (B) metal (C) paper (D) plasti?

SOLUTION: D.

PROBLEM: Question: Roger Bacon is credited for developing the magnifying glass. His understanding of which of these was most useful for this development?  (A) Light (B) Sound (C) Gravity (D) Electricit?

SOLUTION:
A.