Thunder formation during thunderstorms

Thunder is produced by lightning, which causes a sudden rapid expansion of air creating a shock wave. Statement 1 is incorrect: meeting of cumulonimbus clouds itself does not produce thunder. Statement 2 is misleading: lightning doesn't separate nimbus clouds; rather, lightning is the electrical discharge that occurs within or between clouds, and thunder is the sound produced by lightning. Statement 3 is incorrect: violent air and water movement causes storm conditions but not thunder specifically. None of these three statements correctly explains the mechanism of thunder production. Thunder is specifically the acoustic phenomenon resulting from the rapid heating and expansion of air caused by the electrical discharge of lightning. > Thunder = Sound wave from lightning's rapid air expansion, not from cloud collision or air movement. Answer: (d).