There are 4 seats in total.
There are 4 ways to fill 1st seat.
When 1st seat is filled, there will be 3 ways to fill the second seat.
Similarly there will be 2 ways to fill the third seat and 1 way to fill the last seat.
So, total number of ways the seats can be filled = 4 x 3 x 2 x 1 = 24 ways.
Therefore, the correct answer is option A
