The correct answer is d) 725 mmHg.
Pressure is a physical quantity that describes the force exerted by gas particles against the walls of a container. It is commonly measured in units such as atmospheres (atm), pascals (Pa), and millimeters of mercury (mmHg). In this context, 725 mmHg is a direct measurement of pressure, while the other options provided indicate temperature (315 K), mass (1.2 g), volume (2.5 L), and the amount of substance (0.45 moles), none of which are pressure measurements.