Question 1307Navigation General

The correct answer is C) pressure difference over horizontal distance. The pressure gradient is a measure of the change in pressure over a given horizontal distance. It is the rate of change of pressure with respect to the distance in a particular direction, usually horizontally. A higher pressure gradient indicates a more rapid change in pressure over that distance. The other options are incorrect because: A) Vertical pressure variation is not the definition of pressure gradient. B) Pressure difference over time is not the definition of pressure gradient. D) A high-pressure area is a region of high pressure, not a measure of the pressure gradient.