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.

Which statement best compares single-celled and multi-celled organisms?  
 (A) Tissues in a single-celled organism are like the cells in a multi-celled organism. (B) The nucleus in a single-celled organism is like the skin of a multi-celled organism. (C) Organelles in a single-celled organism are like the organs in a multi-celled organism. (D) The cytoplasm in a single-celled organism is like the nervous system in a multi-celled organism.
C

Because water can hold a large amount of heat, which effect do oceans have on nearby land areas?  
 (A) They prevent rapid extreme temperature changes. (B) They form high-pressure areas that cause magma currents. (C) They provide the energy that triggers volcanic events. (D) They lower the freezing point of fresh water.
A

Which of these is an unpiloted spacecraft designed to gather information while orbiting planets other than Earth?  
 (A) space probe (B) space shuttle (C) space station (D) space telescope

A