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.

[EX Q]: Which best describes a characteristic of the jet stream?  
 (A) It forms a boundary between a cold air mass and a warm air mass. (B) It creates the high winds around the eye of a hurricane. (C) It forces the hot air along the equator to rise to areas in North America. (D) It causes high pressure air masses to rotate clockwise.
[EX A]: A

[EX Q]: 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
[EX A]: A

[EX Q]: Which activity would most likely increase water turbidity in a nearby stream?   
 (A) rolling steel into thin sheets (B) burning coal for electricity (C) clear-cutting a forest (D) planting a cover crop
[EX A]:
C