Two Sealed Boxes Are Filled with Gas

Two sealed boxes are filled with gas.The first box contains more molecules moving faster and therefore has a higher pressure.The second box contains fewer molecules moving slower and therefore has a lower pressure.Why does the first box have a higher pressure?

A) The more molecules, the higher the pressure.
B) The more collisions against the side of the box, the higher the pressure.
C) The fewer molecules, the higher the pressure.
D) When there is high pressure, it is harder for molecules to move, so they create heat and pressure.
E) There is no reason for the first box to have high pressure.