A. Acids; pH less than 7
The pH scale is assigned to an agreed standard arrangements whose pH is set up by universal understanding. The scale is between 0 and 14 , values between 0 and 7 are acidic while 7 is neither acidic or base; values greater than 7 are considered as base. In context of the question above, only acids have the characteristics of being corrosive with strong smell so, the correct option is A
