There are three acid-base indicators: methy`1` orange (end point at `pH = 4)`, bromothymol blue (end point `pH = 7)`, and phenolphthalein (end point at `pH = 9)`. Which of the following would you select for the titrations?
a. `H_(2)SO_(4)` with `KOH` b. `KCN` with `HCI`
c. `NH_(3)` with `HNO_(3)` d. `HF` with `NaOH`