You are given a science question (easy-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.

Ex Input:
A population of ground squirrels has established a community in the grasslands of the Great Plains. Temperatures often reach -15°C for most of the winter. What is the most likely behavior the ground squirrels use to survive these winter temperatures?  
 (A) burrowing below the frost point of the soil surface (B) burrowing in tree trunks above the soil surface (C) consuming roots found under the soil surface (D) consuming organisms found in the soil surface

Ex Output:
A


Ex Input:
The North America Nebula is named for its similarity in shape to the North American continent. It was discovered within the Milky Way by astronomer William Herschel in 1790. What was Mr. Herschel most likely observing?  
 (A) the explosion following the collapse of a star (B) a dense cluster of stars of varying magnitudes (C) meteorites as Earth passed through the tail of a comet (D) a cloud of hydrogen gas and dust where stars are born

Ex Output:
D


Ex Input:
If a cell is exposed to a chemical that inhibits the production of spindle fibers as the cell is preparing for mitosis, what would most likely happen?  
 (A) The cell would continue with mitotic division. (B) The cell would undergo meiotic division. (C) The cell would break open. (D) The cell would not divide.

Ex Output:

D