Given the task definition and input, reply with output. 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).

Paragraph: If the gas is cooled, the particles will move more slowly, because they will have less energy.
 Question: John is playing around with different temperature settings on his bunsen burner. If he heats up a gas in the burner and then lets the gas cool down, what would happen to the gas particles as the temperature got lower? 
 Choices: A)they would slow down 
B)they would speed up
they would slow down