Option 1 states that both the assertion (A) and the reason (R) are individually true, and R is the correct explanation of A. Let`s analyze each component separately.

Assertion A states that convectional rains occur during pre-monsoon summer in India. This statement is true. Convectional rains are caused by the intense heating of the land during the summer months, which leads to the formation of thunderclouds and subsequent rainfall.

Reason R states that such rains occur due to adiabatic cooling. Adiabatic cooling refers to the cooling of air as it rises higher in the atmosphere. When air heated by the sun`s radiation rises, it expands and cools, leading to the formation of clouds and rainfall. This is indeed the process that leads to the convectional rains mentioned in Assertion A.

Therefore, in this case, both the assertion and the reason are true, and R correctly explains why convectional rains occur during pre-monsoon summer in India. Hence, option 1 is the correct answer.

It is worth noting that option 2 is incorrect because the reason does provide a correct explanation for the assertion. Option 3 and 4 are also incorrect as both A and R are individually true.