Answer:
The mass will stay the same throughout time
A gas has to become ionisied in order to become a conductor. It must have a chain reaction in which atoms in it became unstable, in which they loose stabile electronic configuration. In order for a gas to become a conductor, it must have free particles, and it can happen only in ionisied gas.

The correct choice is ~ A
Bikes don't require gasoline for their functioning, so it causes less air pollution.