Answer:
option (A)
Explanation:
The a body having rest mass is mo is moving with velocity v which is of the order of velocity of light in vacuum, so the mass of the body increases. According to the formula

As the velocity increases, the mass m of the body increases. As the velocity of the object is equal to the velocity of light in vacuum, then the mass of the body becomes infinite.
Answer;
2 g/cm³ or 2000 kg/m³
Solution;
Density is given by dividing the mass of a substance by its volume.
Density = Mass/volume
Mass = 36 g
Volume = length × width × height
= 6 cm × 3 cm × 1 cm
= 18 cm ³
Therefore;
Density = 36 g/ 18 cm³
= 2 g/cm³ or 2000 kg/m³