Which of the following quantities related to an electron has a finite upper limit?

If the electron is moving with very high-speed v, then its mass will increase by the factor i.e. m’= m, where ,

Momentum, p = m’v=

Kinetic energy k=

When the speed of electron is maximum i.e. v=c, then

Therefore, the upper limit of speed is always less than c but mass, momentum and kinetic energy do not have any upper limit.

Option (c) is correct.