Answer : The correct option is, pressure and volume
Explanation :
Boyle's law : According to the Boyle's law, the pressure of the gas is inversely proportional to the volume of the gas at constant temperature of the gas and the number of moles of the gas.
\(P\propto \frac{1}{V}\\\\PV=k\)
where,
P = pressure of the gas
V = volume of the gas
k = constant
That means in the Boyle's law, pressure and the volume are the variables and temperature and number of moles are constant.
Hence, the correct option is, pressure and volume
