The mass of a body :

1. changes with a change of place
2. changes with direction
3. changes when the velocity of the body is close to the velocity of light
4. none of these

changes when the velocity of the body is close to the velocity of light

Reason — The mass of a body increases with its velocity but this change is perceptible only when the velocity of the body v becomes more than 10⁶ ms^-1 i.e., reaches close to the speed of light c = (3 x 10⁸ ms^-1), so for a body moving with velocity less than 10⁶ ms^-1, its mass is taken to be constant.