Answer:
The correct answer is a. The volume of the gas increases.
Step-by-step explanation:
In this case, we apply Boyle Mariotte's Law: for a given gas mass at constant temperature, the pressure and volume vary inversely proportionally (the higher the pressure, the lower the volume and vice versa).
If the pressure reduced, the volume increases according to the formula: P1xV1 = P2xV2