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.

[Q]: Students shake salt into a jar of water, and they shake pepper into a second jar of water. Which statement best compares the two jars?  
 (A) Only the salt and water is a mixture. (B) Only the pepper and water is a solution. (C) Both jars contain solutions. (D) Both jars contain mixtures.
[A]: D


[Q]: What MAJOR advantage does nekton have over plankton in locating food?  
 (A) Nekton can actively swim. (B) Nekton can see in the dark. (C) Nekton do not eat much food. (D) Nekton can eat anything in the ocean.
[A]: A


[Q]: Jerry threw a ball into the air. It followed a curved path and soon fell to the ground because  
 (A) air friction stopped the ball. (B) gravity changed the ball's direction. (C) the ball was not thrown hard enough. (D) the ball was not thrown straight up.
[A]:
B