Answer is: A) it would increase .
Boyle's Law (the pressure-volume law): volume of a given amount of gas held at constant temperature varies inversely with the applied pressure when the temperature and mass are constant.
p₁V₁ = p₂V₂ (the product of the initial volume and pressure is equal to the product of the volume and pressure after a change).
For example:
p₁ = 1.2 atm; starting pressure.
V₁ = 2.0 L., starting volume.
V₂ = 1.0 L; final volume, smaller than starting volume.
p₂ = ?; final pressure.
1.2 atm · 2 L = p₂ · 1 L.
p₂ = 1.2 atm · 2 L / 1 L.
p₂ = 2.4 atm.
When volume goes up, pressure goes down.
When volume goes down, pressure goes up.