instruction:
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.
question:
Which of the following has the least momentum?
(A) a 0.5 kg mass with a 1000 m/s velocity (B) a 1 kg mass with a 100 m/s velocity (C) a 10 kg mass with an 11 m/s velocity (D) a 100 kg mass with a 2 m/s velocity
answer:
B

question:
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.
answer:
A

question:
What is the frequency of ocean waves that have a speed of 18 m/s and a wavelength of 50 m?
(A) 0.18 Hz (B) 0.36 Hz (C) 2.8 Hz (D) 9.0 Hz
answer:
B