An ideal gas is enclosed in a cylinder at pressure of 2 atm and temperature, 300 K. The mean time between two successive collisions is 6×10−8 s. If the pressure is doubled and temperature is increased to 500 K, the mean time between two successive collisions will be close to
(a) 4×10−8 s
(b) 3×10−6 s
(c) 2×10−7 s
(d) 0.5×10−8 s