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.

[EX Q]: The cactus moth was deliberately introduced to Australia in 1926 as a biological control for an invasive prickly pear cactus. By the early 1990s the moth had also migrated to the Florida Keys from South America and the moth soon eliminated most of the semaphore cacti in the region. Since then, the moth has adapted to eat other plants in the Keys and has continued to grow in number. Which procedure would most likely reduce the population of the cactus moth?
(A) Release sterile moths to limit reproduction. (B) Use widespread spraying of insecticides. (C) Introduce a predator of the cacti. (D) Stop importation of all types of plants.
[EX A]: A

[EX Q]: Nearly 100 years ago, a large volcano erupted in the South Pacific. The following year, Boston recorded measurable snow every month of the year, and most of the Northern Hemisphere experienced a cold summer. Which explains how these two events were related?
(A) The eruption intensified the greenhouse effect. (B) Lava flow from the eruption caused a temporary increase in Earth's total heat energy. (C) The eruption caused damage to the ozone layer. (D) Air pollution from the eruption caused a decrease in the amount of solar energy reaching Earth.
[EX A]: D

[EX Q]: Scientists launch a rocket into space for a mission. Once the rocket escapes the gravitational pull of Earth, how will the mass and weight of the rocket be affected?
(A) The mass and weight will change. (B) The mass and weight will stay the same. (C) The mass will stay the same, but the weight will change. (D) The mass will change, but the weight will stay the same.
[EX A]:
C