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.

Scientists have discovered fossils of the same organisms in many different parts of the world. These fossils provide evidence that  
 (A) the continents were once joined together (B) most life-forms that existed in the past are still present today (C) most of Earth's surface was once covered by molten rock (D) rocks have been transformed from one type to another
A

A pharmaceutical company developed a drug to help relieve headaches. Recently, the pharmaceutical company discovered that the drug may cause nausea in a small number of people who might take the drug. Which is the most ethical course of action that the drug company could take?  
 (A) Discontinue the use of the drug. (B) Inform people of the possible side effects. (C) Reduce the amount of drug given to people. (D) Modify the drug to include medicine that prevents nausea.
B

Which of the following describes water changing from liquid to solid?  
 (A) ice forming on a lake (B) dew forming on grass (C) snow melting into a puddle (D) water evaporating from a pond

A