Correct Answer - Option 4 : n!
Given
In how many ways can we arrange 'n' things in a row
Calculation :
Number of ways of arrange n things(If n = 5!)
⇒ 5× 4 × 3 × 2× 1 = 120 ways to arrange fine objects .
In general say that there are n! permutations of n objects . This quantity nCr is called the "combination" and represents the probability of picking r distinguishable outcomes out of n without regard to the order of picking each outcome.
∴ The required answer is n!.