How do temperature, humidity, and pressure vary within an air mass? A. Temperature and humidity vary, but pressure does not.

B. Humidity makes the pressure in an air mass increase.

C. Temperature, humidity, and pressure are basically the same all through an air mass.

D. Temperature at the border of an air mass is always higher than in the middle.

Make sure to give me an explanation so I don't get dirt about me cheating. I just really need to know this simple question. Please, be so helpful.