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: When a volume of water is cooled, the molecules move less vigorously, so same number of molecules takes up less space and the water is denser.
 Question: If Mona fills up a cup with water and places that water into the oven, what happens to the density of the water as it heats up? 
 Choices: A)increases 
B)decreases
decreases