Given below are two statements: one is labelled as Assertion and the other is labelled as Reason .
Assertion A: Phenolphthalein is a dependent indicator, remains colourless in acidic solution and gives pink colour in basic medium.
Reason R: Phenolphthalein is a weak acid. It doesn't dissociate in basic medium.
In the light of the above statements, choose the most appropriate answer from the options given below.