Task: Question Answering
Input (English): Question: A and B can together finish a work in 10days. They worked together for 5days and then B left. After another 5days, A finished the remaining work. In how many days A alone can finish the job?

 Option A: 10

 Option B: 15

 Option C: 20

 Option D: 5

 Option E: 30
Output (English): Option A