TASK DEFINITION: You are given a question or fill-in-the-blank question, two answer options (Option1 and Option2) and an Explanation. Your task is to find the correct answer (return the string of the correct option, not option1/2) for the given question from the given options and using explanation.
PROBLEM: Question: Fred has an isotope that decays quickly. What is likely true about it? 
 Option1: it can be used to date older specimens 
 Option2: it can't be used to date old specimens 
 Explanation: Because these isotopes decay more slowly, they can be used to date much older specimens.

SOLUTION: it can't be used to date old specimens

PROBLEM: Question: If you fill a large canister with gas from a smaller canister will the density 
 Option1: increase 
 Option2: decrease 
 Explanation: If we take a certain amount of gas from one container and place it into another, larger container, the gas expandsto fill the larger container. The same mass of gas is now in a larger volume, the gas now has a lower density.

SOLUTION: decrease

PROBLEM: Question: Compared to sound waves travelling through a cup of boiling water, would sound waves travelling through a cup of ice water move 
 Option1: slower 
 Option2: faster? 
 Explanation: For a given medium, sound waves travel more slowly at lower temperatures.

SOLUTION:
slower