D. convection
Explanation:
The four main mechanisms that lift the air in the atmosphere and create clouds are a) Convection; b) Convergence; c) Updraft and d) Orographic Lifting
Radiation, conduction and water vapor are not responsible for creating lift in the atmosphere. Β
In convection, heat energy from sun raises the temperature of surface of the earth as it passes through the atmosphere. The air near the surface become less dense Β and hence starts rising thereby creating a lift.
Hence, option D is correct