A tank with an open top has an opening of 1 cm radius that is 4 m below the water level in the tank. The volume of water that would drain out per minute is: (Tank is large, take g = 10 m/s²).
(a) π cm³/min
(b) 2π cm³/min
(c) 4π cm³/min
(d) 8π cm³/min