To determine the correct measuring unit for the pressure of a liquid, let's review each option given:
Α. Liter: This is a unit of volume, not pressure. A liter measures the amount of space a liquid occupies.
B. Fathom: This is a unit of length, primarily used in measuring the depth of water. One fathom equals six feet.
C. Gallons per minute: This is a unit of flow rate, which indicates how many gallons of liquid flow in one minute. It does not measure pressure.
D. Pounds per square inch: This is a unit of pressure. It measures the force exerted on a surface area and is commonly used to describe the pressure of liquids, gases, and other substances.
Given that the question asks for the unit used to measure the pressure of a liquid, the correct answer is:
D. Pounds per square inch