It's "C" a sample of dust particles at 0 Pascals
When temperature increases pressure also increases.
When temperature decreases pressure decreases.
That is why you have low tire pressure when it’s cold out
1 mole = 6.22 x 10^23 molecules (Avogadro's number)
15 moles x (6.22 x 10^23) = 9.33 x 10^24 atoms
