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.

[Q]: A delta at the mouth of a river is the direct result of
(A) runoff from sewage. (B) deposition of sediment. (C) an ancient glacier that passed through. (D) an underground river flowing to the ocean.
[A]: B

[Q]: A bright object with a long tail of glowing gases is in orbit around the Sun. This object is most likely
(A) a planet (B) a star (C) an asteroid (D) a comet
[A]: D

[Q]: What aspect of the DNA molecule encodes hereditary information concerning an organism's traits?
(A) the molecular mass (B) the sequence of base pairs (C) the distribution of electrical charges (D) the folded three-dimensional shape
[A]:
B