6) Clouds normally form at pressure systems because *

a) Low; The air here is coming together in the middle of the system, rising, cooling,
and condensing.
b) High; The air here is coming together in the middle of the system, rising, cooling,
and condensing.
c) Low; The air here is coming together and sinking then diverging (separating) along
Earth's surface
d) High; The air here is coming together and sinking then diverging (separating) along
Earth's surface
Please don't give links for the answer. Thanks!