A fluid is flowing in the 4 in. diameter cylinder of a hydraulic system. when 4 points
 activated the piston moves 3 ft. in 15 seconds. (144 inches/minute). what
 is the flow rate, in gallons per minute of the cylinder? *
 a. 576 gal./min.
 b. 2.5 gal./min
 c. 7.8 gal./min
 d. 1808 gal./min