The state of a gas can be described by quoting the relationship between:

1.  Pressure, volume, temperature

2.  Temperature, amount, pressure

3.  Amount, volume, temperature

4.  Pressure, volume, temperature, amount

Hint:  Follow Ideal gas equation.

Explanation: 

The state of a gas can be described by quoting the relationship between pressure, volume, temperature and amount. The Ideal gas equation is
pV=nRT
Thus, p, V, T and n described the state of the system.