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]: Which land feature is most likely the result of a glacier?  
 (A) large, arid desert (B) deep, bowl-shaped lake (C) long crack in the ground (D) volcanic mountain range
[EX A]: B

[EX Q]: A wetland habitat can continue to support the birds and fish that live there if people ___.  
 (A) drain the water away (B) flood the highest parts of the land (C) leave the land alone (D) use the land for planting crops
[EX A]: C

[EX Q]: The Sun is approximately 1.5 x 10^8 km from Earth. The speed of light is 3.0 x 10^8 m/sec. What is the distance from the Sun to Earth in light-seconds?  
 (A) 2.0 light-seconds (B) 0.5 light-seconds (C) 2.0 x 10^-3 light-seconds (D) 5.0 x 10^2 light-seconds
[EX A]:
D