If you push and push on an object to increase its velocity $($like a particle in an

accelerator$).$ What happens to its mass as the velocity becomes larger and larger?

a$.$ The mass decreases to $0$ when it reaches the speed of light.

b$.$ The mass increases until it doubles when it reaches the speed of light.

c$.$ The mass increases towards infinity as its speed approaches the speed of

light.

d$.$ Its mass remains the same but it becomes easier to accelerate the particle

as its speed gets closer to the speed of light.

e$.$ Its mass remains the same because mass is conserved $($remains the same$)$

in general relativity.