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 Q]: Which type of organism is at the lowest level of the food chain?  
 (A) autotroph (B) heterotroph (C) carnivore (D) omnivore
[EX A]: A

[EX Q]: People are developing electric cars that would replace gasoline-burning cars. One major advantage of the electric car is that it  
 (A) accelerates faster. (B) causes less pollution. (C) gives a smoother ride. (D) needs no battery.
[EX A]: B

[EX Q]: What keeps the planets in orbit around the Sun?  
 (A) air resistance (B) friction (C) gravity (D) magnetism
[EX A]:
C