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).

Ex Input:
Question: Which method below would be the best way to determine if an egg, plastic foam, a piece of wood, or a candle would float on water?  (A) observing each object in water (B) measuring the size of each object (C) calculating the weight of the objects (D) comparing the shapes of the object?

Ex Output:
A.


Ex Input:
Question: Where will fossil fuels most likely be found?  (A) High in the atmosphere (B) Underground (C) Floating on the ocean (D) In the hydrospher?

Ex Output:
B.


Ex Input:
Question: Water freezing is an example of a  (A) liquid changing to a solid (B) solid changing to a liquid (C) gas changing to a solid (D) gas changing to a liquid?

Ex Output:

A.