Why is the rate of diffusion of $\ce{NH3}$ greater than $\ce{HCl}$?

Question

Accepted Answer

$\ce{NH3}$ has lesser molecular mass (17 vs 36.5)

Answer

$\ce{NH3}$ is heavier

Answer

$\ce{HCl}$ is colder

Answer

They are equal

Why is the rate of diffusion of NHX3\ce{NH3}NHX3​ greater than HCl\ce{HCl}HCl?