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.

A model of the Moon would be different from a model of Earth in that the Moon should  
 (A) be smaller than Earth. (B) have a source of light inside. (C) have a smoother surface than Earth. (D) have fewer impact craters on the surface.
A

When manned space exploration began, NASA used the gravity assist concept so that spacecraft could conserve fuel. Which statement explains why the gravity assist concept was useful for spacecraft to successfully travel and return to Earth?  
 (A) It gave spacecraft a timed trajectory. (B) It ensured spacecraft would return home safely. (C) It was helpful in planning spacecraft trajectories. (D) It ensured spacecraft would avoid being pulled into the sun.
C

In snapdragon plants, red flowers are dominant to white flowers. When red-flowered plants are crossed with white-flowered plants, pink flowers are produced. If a researcher wants to produce plants with only white flowers, what color should the parent plants be?  
 (A) both red (B) both white (C) one red and one white (D) one white and one pink

B