A 350 m^3 retention pond that holds rainwater from a shopping mall is empty at the beginning of a rainstorm. The flow rate out of the retention pond must be restricted to 320 L/min to prevent downstream flooding from a 6-hour storm. What is the maximum flow rate (in L/min) into the pond from a 6-hr storm that will not flood it? a. 5,860 L/min b. 321 L/min c. 1.290 L/min d. 7.750 L/min