9. In PMU's auditorium, you are in charge of seating the Prince, the Prince's Son, the Rector, the
Vice-Rector, and the Dean of student affairs, at the head table of the auditorium. In how many
ways can you seat the guests in the 5 chairs on one side of the table?
Hint: $P(n,r) = \frac{n!}{(n-r)!}$ and $C(n, r) = \frac{n!}{r!(n-r)!}$.
A: 121 B: 24 C: None D: 122.