Detailed Instructions: 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.
Q: Question: Mary melts a 1 pound chocolate bar and 1 pound of chocolate chips in two pots. Which melts last? 
 Option1: bar 
 Option2: chips 
 Explanation: It would be hard to get a big chunk of chocolate to dissolve in your milk or hot water. Maybe you could make hot chocolate from some smaller pieces like chocolate chips, but it is much easier to add a powder to your milk. This is because the smaller the pieces are, the more surface area they have.
A:
bar