Task: Question Answering
Input (English): Question: A and B can do a piece of work in 45 days and 40 days respectively. They began to do the work together but A leaves after some days and then B completed the remaining work in 23 days. The number of days after which A left the work was

 Option A: 5 days

 Option B: 6 days

 Option C: 7 days

 Option D: 9 days

 Option E: 8 days
Output (English): Option D