Correct Answer - C
Rule `(A A A):` In acid buffer `(A)`, on addition of `S_(A)(A)`, the concentration of `W_(A)(A)` increases and that of salt decreases, so `pH` decreases.
`pH = pK_(a) +"log"(["Salt" -x])/(["Acid" + x])`
`(x` is the concentartion of `H_(2)SO_(4)` added)