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 Input:
Which set contains kingdoms that contain only heterotrophs?   
 (A) Protists, Fungi (B) Bacteria, Animals (C) Plants, Fungi (D) Animals, Fungi

Ex Output:
D


Ex Input:
Which of these will best separate a saltwater solution?  
 (A) using a paper filtering system (B) using chromatography (C) allowing the salt to settle (D) allowing the water to evaporate

Ex Output:
D


Ex Input:
Which rock is most likely to contain fossil seashells?  
 (A) basalt (B) gneiss (C) granite (D) limestone

Ex Output:

D