Task: Question Answering
Input (English): Question: On selling 20 balls at Rs. 720, there is a loss equal to the cost price of 5 balls. The cost price of a ball is:

 Option A: s. 48

 Option B: s. 50

 Option C: s. 55

 Option D: s. 60

 Option E: s. 70
Output (English): Option A