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]: Petrified palm trees are found in sedimentary rock near glaciers. The presence of the petrified palm trees most likely provides evidence for which statement?  
 (A) There was once more water in the area. (B) The area was once grassland. (C) The climate in the area was once tropical. (D) There are active faults in the area.
[EX A]: C

[EX Q]: A scientist makes a discovery while performing an investigation, but fails to maintain clear records of the tests performed. In which way does a lack of record keeping affect a scientist's work?  
 (A) It invalidates the procedures and conclusions. (B) It makes the data obtained in the study incorrect. (C) It prevents other scientists from validating the results. (D) It prohibits other scientists from developing new hypotheses.
[EX A]: C

[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