The correct option is B.
Phenophtalein is an indicator that is usually used in acid base titration experiments. Indicators are substances that undergo distinct, observable changes when the pH of their solutions change. Indicators exhibit changing of colors depending on the pH of the solution in which they are found. They are usually weak bases and acid which are capable of partial dissociation and formation of ions when dissolved in water. There are different types of indicator and phenophtalein is one of them. Phenophtalein is colorless in acidic solution and pink in basic solutions.
