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: The air gets thicker when it is 
 Option1: hot 
 Option2: cold 
 Explanation: Increasing air temperature decreases atmospheric pressure.

SOLUTION: cold

PROBLEM: Question: If we keep filling a balloon with oxygen particles what happens to the pressure? 
 Option1: increases 
 Option2: decreases 
 Explanation: More particles inside the container means more collisions, and more collisions mean a higher pressure.

SOLUTION:
increases