Which sentence correctly states Boyle’s law?

A.
The pressure on a gas varies inversely with its volume at constant temperature.
B.
The pressure on a gas varies directly with its volume at constant temperature.
C.
The pressure on a gas varies directly with its temperature at constant volume.
D.
The pressure on a gas varies inversely with its temperature at constant volume.
E.
The volume of a gas varies directly with its temperature at constant pressure.