What is the reason of ‘stone-cancer’? , What is the reason of ‘stone-cancer’?

Solution

C. Acid rain

Explanation

Stone cancer is caused by the acid rain and it is actually the state when the buildings especially those made up of marble get eroded and fainted as an adverse consequence of acid rain that falls on them. It can simply be understand by the sentence that ‘stone monuments like Taj mahal’ are being eroded due to stone cancer by acid rain.