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]: What force pulls things towards the center of Earth?  
 (A) magnetism (B) gravity (C) friction (D) energy
[EX A]: B

[EX Q]: During which stage of an insect's life cycle does the female lay eggs?  
 (A) nymph (B) larva (C) pupa (D) adult
[EX A]: D

[EX Q]: Which invention uses natural magnetism?  
 (A) satellite (B) telescope (C) compass (D) binoculars
[EX A]:
C