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.

[EX Q]: Question: If Mona shines a light through both wool and cotton and determines that cotton is more dense then wool, which material will the light move faster through? 
 Option1: wool 
 Option2: cotton 
 Explanation: The more dense the medium, the slower the light moves.
[EX A]: wool

[EX Q]: Question: Will drilled 1000 feet to find a rock. Harry picked a rock up off of the ground. Whose rock is likely older? 
 Option1: Will 
 Option2: Harry 
 Explanation: Therefore, deeper rock layers must be older than layers closer to the surface.
[EX A]: Will

[EX Q]: Question: Fred has an isotope that decays slowly. 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.
[EX A]:
it can be used to date older specimens