The moment when jadish got order of promotion, as General Manager, was a memorable occasion for him and his family.

B. immemorial means “existing from time immemorial; of unknown or very ancient origin.” This does not fit the context of the sentence, as the moment when Jadish got the order of promotion was a specific moment in time.

C. forgetful means “having or showing a tendency to forget things.” This does not fit the context of the sentence, as Jadish and his family clearly remembered the moment when he got the order of promotion.

D. innocuous means “harmless or not serious.” This does not fit the context of the sentence, as the moment when Jadish got the order of promotion was a significant moment in his life.