The Neutrino Has Been Shown to Have a Small Mass

The neutrino has been shown to have a small mass. What difference does that make in determining its speed?

A) Because it is a particle with mass, its speed is governed by the temperature of its surroundings because it will always be in thermal equilibrium.
B) Because it is a particle with mass, its speed must be less than the speed of light, c.
C) Its speed must be faster than the speed of light, because this is the only way that a lepton can have mass.
D) Because of its nature, a neutrino can only exist when it is traveling at the speed of light, just like photons of electromagnetic radiation.