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.

Early scientists most likely saw a discharge of electricity for the first time when observing a  
 (A) waterfall (B) rainbow (C) lightning storm (D) volcano erupting
C

Which of the following best describes a role of mushrooms in ecosystems?  
 (A) capturing energy from sunlight (B) consuming living plant material (C) taking energy from animal hosts (D) breaking down dead plant material
D

Which of the following is a benefit of using radiation as a medical treatment?  
 (A) It kills cancer cells. (B) It produces healthy cells. (C) It improves immune system function. (D) It prevents many forms of illness in patients.

A