Extensive properties are the properties of the system which depend upon the quantity or size of matter present in it.

Examples: Mass, volume, internal energy, boiling point, ph and mass/volume( density)

Intensive properties are those properties which are independent of the quantity or size of matter present in it.

Intensive properties are physical or chemical properties that do not depend on the amount or size of the sample being observed. These properties remain the same regardless of the scale or quantity of the substance. In the given options, boiling point (I), pH (III), and density (IV) are all examples of intensive properties.

Boiling Point (I):
The boiling point of a substance is the temperature at which it changes from a liquid to a gas at a given pressure. Boiling point is an intensive property because it does not depend on the amount of substance present. For example, water boils at 100 degrees Celsius at sea level regardless of whether you have a small amount or a large amount of water.

pH (III):
pH is a measure of the acidity or alkalinity of a solution. It is defined as the negative logarithm of the concentration of hydrogen ions (H+) in a solution. pH is an intensive property because it is independent of the amount of solution being observed. For example, a solution with a pH of 7 is neutral whether you have a small amount or a large amount of the solution.

Density (IV):
Density is the mass of a substance per unit volume. It is calculated by dividing the mass of the substance by its volume. Density is an intensive property because it remains constant regardless of the size or amount of the substance. For example, the density of gold is 19.3 grams per cubic centimeter, whether you have a small nugget or a large block of gold.

Therefore, the correct answer is option 'C' (I, III, IV) because boiling point (I), pH (III), and density (IV) are all examples of intensive properties that do not depend on the amount or size of the sample being observed.