Does it mean immediate right, or right in general?
The answer would be different in both cases.
I am going to assume it means right in general, because “immediate” is not mentioned anywhere.
The total ways in which we can arrange these 8 letters = 8!
The total ways in which we can arrange the letters A,B,C = 3! = 6
Of the 6 total ways in which we can arrange A, B, C; only 1 will satisfy the condition given in the equation, (ie item B is to be placed to the right item of A, and item C is to be placed to the right of item B)
This means only 1/6 of the total arrangements of the 8 letters will satisfy this condition.
Answer = 1/6 * 8! = 6720 (E)