Which of the following statements about the Maxwell-Boltzmann distribution of molecular speeds are correct?

1. AThe distribution curve starts from the origin and approaches zero asymptotically at high speeds
2. BAt a given temperature, a heavier gas has a narrower distribution with a lower most probable speed
3. CThe area under the curve between two speeds gives the fraction of molecules with speeds in that range
4. DThe average speed is greater than the rms speed