Answer:
The correct option is (b) "pressure".
Explanation:
Gay-Lussac's law states that the pressure of an ideal gas is directly proportional to its temperature at constant mass and volume.
Mathematically, Gay-Lussac's law is as follows :
[tex]P=kT[/tex]
or
[tex]\dfrac{P_1}{T_1}=\dfrac{P_2}{T_2}[/tex]
Hence, the correct option is (b) "pressure".