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.

The cells of a plant help the plant maintain its life functions. What part of a plant cell has the function of producing sugar in the presence of sunlight?  
 (A) chloroplast (B) cytoplasm (C) mitochondria (D) nucleus
A

Which of the following is closest to the percentage of the total water on earth that is freshwater?  
 (A) 100% (B) 90% (C) 70% (D) 3%
D

Which of the following are formed when two crustal plates collide with one another?  
 (A) hot spots (B) rift valleys (C) mountain ranges (D) mid-ocean ridges

C