Which of the 3 variables that apply to equal amounts of gases are directly proportional?

I only have two of the variables. I will try to find a third one if you want me to

Temperature and Pressure
Temperature and Volume

specific gravity is the density of a substance divided by the density of water. since (at standard temperature and pressure) water has a density of 1 gram/cm3, and since all of the units cancel, specific gravity is usually very close to the same value as density

so "c" is the answer

plz give brainliest

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.