Answer : 3. "Thunder"
Explanation :

Answer: C) Thunder Explanation: The Sound Following the flash of lighting is because of Thunder.   Lightning is seen earlier than thunder because light travels much faster than sound.   The roar of thunder is the result of a shock wave produced when lightning super-heats the air through which it passes, causing that air to expand very rapidly. This rapid expansion of air creates a shock wave that travels outward at close to the speed of sound.