Task: Question Answering
Input (English): Question: The Lucknow-Indore Express without its rake can go 24 km an hour, and the speed is diminished by a quantity that varies as the square root of the number of wagon attached. If it is known that with four wagons its speed is 20 km/h, the greatest number of wagons with which the engine can just move is

 Option A: 144

 Option B: 140

 Option C: 143

 Option D: 124

 Option E: 142
Output (English): Option C