The correct answer is option A.
D = M/V
The density of a substance is the ratio of its mass to its volume.
Density = mass / volume
or D = M/V
The unit of density is gram per milliliter or g/ml, when mass is expressed in gram or g and the volume is expressed in milliliter ml.
If we know the mass and volume of a substance we can calculate its density using the formula for density.