TASK DEFINITION: You are given a science question (hard-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.
PROBLEM: If an atom of hydrogen gives up one electron, what is its overall charge?  
 (A) -1 (B) +1 (C) -2 (D) +2

SOLUTION: B

PROBLEM: As Archie walks to the park, he wonders which route would be faster. He decides to walk to the park using different routes and times how long it takes. Which should he do to make his comparison fair?  
 (A) walk to different parts of the park each day (B) walk with a different friend each day (C) walk at the same speed each day (D) walk at the same time of the day

SOLUTION: C

PROBLEM: What precaution must be taken by students when making observations of the Sun?  
 (A) Use only new equipment. (B) Use a very strong telescope. (C) Project image onto a piece of cardboard. (D) Look at the Sun only in the morning.

SOLUTION:
C