Two venturimeters of different area ration are connected at different locations of a pipeline to measure discharge. Similar manometers are used across the two venturimeters to register the head differences. The first venturimeter of area ratio 2 registers a head difference 'h' while the second venturimeter registers '5h?. The area ratio for the second venturimeter is:

• A. 3                                 
• B. 4
• C. 5                                 
• D. 6