The correct options are
A Historians can help with the dialogues, costumes and environment of a period drama.
B Historians can help educate people about the past through tv shows.
C Historians can help in maintaining the authenticity of the event being dramatised.
Television provides a massive opportunity for historians. Shows based on the past like the Ramayan, Bharat Ek Khoj require historians to verify and design the costumes, environment and the dialogues. They also can provide inside into the event being dramatised. Through documentaries and TV shows on channels like History, National Geography and Discovery, historians can educate people about the past.