Task: Question Answering
Input (English): Question: 36 people {a1, a2, ..., a36} meet and shake hands in a circular fashion. In other words, there are totally 36 handshakes involving the pairs, {a1, a2}, {a2, a3}, ..., {a35, a36}, {a36, a1}. Then size of the smallest set of people such that the rest have shaken hands with at least one person in the set is

 Option A: 11

 Option B: 12

 Option C: 13

 Option D: 15

 Option E: 18
Output (English): Option B