You are given a short paragraph, a question and two choices to answer from. Choose the correct answer based on the paragraph and write the answer(not the key).

[EX Q]: Paragraph: To reduce friction, oil is added to the engine.
 Question: Jeff should add _____ to his engine to decrease the friction in its processes. 
 Choices: A)oil 
B)gas
[EX A]: gas

[EX Q]: Paragraph: Water becomes more dense when it is colder and when it has more salt.
 Question: What happens to water when it absorbs less salt? 
 Choices: A)lower density 
B)Higher Density
[EX A]: lower density

[EX Q]: Paragraph: The more dense the medium, the slower the light moves.
 Question: A very rarefied medium will cause light to move 
 Choices: A)faster 
B)slower
[EX A]:
faster