Please help an idiot?

42

Assuming the order matters:
P(5,5) = 5! = 120

If order does not matter:
C(5,5) = 1

In how many ways can five students be seated in a row of five seats?
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a. C(5, 5) =156
b. C(5, 5) =136
c. P(5, 5) =84
d. P(5, 5) =120

Please explain. thank you

Ok... u need to add the question the details