Answer : 3. "5040"
Explanation :

Answer: C) 5040 Explanation: The number of ways in which the letters of the word RAILINGS can be arranged such that R & S always come together is   Count R & S as only 1 space or letter so that RS or SR can be arranged => 7! x 2!   But in the word RAILINGS, I repeated for 2 times => 7! x 2!/2! = 7! ways = 5040 ways.