I am unsure about the actual question,
But if you need to choose two answers, I would do B and C
B; convection currents are responsible for many things like air flow, the amount of humidity, and so much more.
C; Warmer air moves through these convection currents towards cooler regions, which affects the temperature.
The two answers work hand in hand-
So if that is what the question is asking, the answers are B and C