Choose the correct statement(s) about buffer capacity during titration of `NH_(4)OH` with `HCl`:
A. Buffer capacity during titration first increases then decreases
B. Buffer capacity reaches to maximum at equivalence point.
C. Buffer capacity will increase if concentration of `NH_(4)OH` increases.
D. Buffer capacity value will remain same if strong acid `HCl` is replace by `H_(2)SO_(4)` of equal `[H_(2)O]`