Duringathunderstorm,thethunder in the sky is produced by the 1. meeting of cumulonimbus clouds in the sky. 2. lightning
Let me explain it simply. The question is asking about duringathunderstorm,thethunder in the sky is produced by, and the answer is None of the above. In Cloud, None of the above is the name you will see again and again for this topic. Read it twice, say it once, and it will stick.
Ref: [IAS (Pre) 2013] | NCERT Geography textbooks and Goh Cheng Leong, Certificate Physical and Human Geography, discuss Cloud and explain the geographical concepts and processes that support the correct answer for this question.