Avogadro’s law and charles’s law describe a proportionality of the volume of a gas when the pressure is constant. which describes the proportionality that allows these laws to be combined when describing a gas?
volume is directly proportional to temperature (avogadro’s law) and to moles (charles’s law).
volume is inversely proportional to temperature (avogadro’s law) and to moles (charles’s law).
volume is directly proportional to moles (avogadro’s law) and to temperature (charles’s law).
volume is inversely proportional to moles (avogadro’s law) and to temperature (charles’s law).

Answer : The correct option is, Volume is directly proportional to moles (Avogadro’s law) and to temperature (Charles’s law).

Explanation :

As we know that, there are four law of gas which are :

1) Boyle's Law : It is defined as the pressure of the gas is inversely proportional to the volume of the gas at constant temperature and number of moles.

    (At constant temperature and number of moles)

2) Charles' Law : It is defined as the volume of the gas is directly proportional to the temperature of the gas at constant pressure and number of moles.

   (At constant pressure and number of moles)

3) Gay-Lussac's Law : It is defined as the pressure of the gas is directly proportional to the temperature of the gas at constant volume and number of moles.

    (At constant volume and number of moles)

4) Avogadro's Law : It is defined as the volume of the gas is directly proportional to the number of moles of the gas at constant pressure and temperature.

  (At constant temperature and pressure)

Hence, from the above information we conclude that the correct option is, Volume is directly proportional to moles (Avogadro’s law) and to temperature (Charles’s law).

i'm assuming that the correct answer is indeed the first one/ "a"..

i think the answer is terrae but not 100 percent sure. ▓▬▬ §