ANS:C - specific gravity

To find the specific weight, specific mass, or specific gravity of a liquid, we need to understand these terms:

1. Specific weight: This refers to the weight per unit volume of a substance. It is calculated as the weight of the substance divided by its volume.
2. Specific mass: This is the mass per unit volume of a substance. It is calculated as the mass of the substance divided by its volume.
3. Specific gravity: This is a dimensionless ratio of the density of a substance to the density of a reference substance (usually water at 4 degrees Celsius). Since specific gravity is a ratio of densities, it has no units.

Given that the liquid weighs 3000 kg and has a volume of 4 cubic meters, we can find the specific weight, specific mass, and specific gravity.

1. Specific weight: Specific weight = Weight / Volume Specific weight = (3000 kg) / (4 cubic meters) = 750 kg/m³
2. Specific mass: Specific mass = Mass / Volume Specific mass = (3000 kg) / (4 cubic meters) = 750 kg/m³
3. Specific gravity: Specific gravity = Density of liquid / Density of water at 4°C Specific gravity = (3000 kg / 4 cubic meters) / (1000 kg / 1 cubic meter) = 0.75

From the calculations, we find that 0.75 is the specific gravity of the liquid. Therefore, the correct answer is: specific gravity.