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 red flowered plant (RR) is crossed with a white flowered plant (WW) and produces plants with pink flowers (RW). If two pink flowered plants are crossed, what color offspring could be produced?  
 (A) red, white, and pink (B) red and white (C) pink and red (D) pink and white
A

When oxygen combines with hydrogen, which substance is formed?  
 (A) water (B) vinegar (C) hydrochloric acid (D) hydrogen dioxide
A

Which distance is the smallest for which it is most practical to use the light-year as a unit of measurement?  
 (A) the distance between Earth and its Moon (B) the distance between Jupiter and the Sun (C) the distance between the Milky Way and the nearest galaxy (D) the distance between the Sun and the center of the Milky Way

D