Task: Question Answering
Input (English): Question: Set K contains every multiple of 6 from 18 to 306 inclusive. If w is the median of set K, and x is the average (arithmetic mean) of set K, what is the value of w-x?

 Option A: -6

 Option B: -3

 Option C: 0

 Option D: 3

 Option E: 6
Output (English): Option C