Amitabh Bachchan's full name is Amitabh Harivansh Bachchan, where 'Harivansh' is his father's name (poet Harivansh Rai Bachchan). Option A incorrectly uses 'Rai' as the middle name instead of 'Harivansh'. Option C adds an extra 'rai' suffix which is incorrect. Option D is incomplete.