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For 2 le r le n, (n/r) + 2(n/(r-1)) + (n...

For `2 le r le n`, `(n/r) + 2(n/(r-1)) + (n/(r-2))` =

A

a) `((n+1)/(r-1))`

B

b) 2 `((n+1) / (r+1))`

C

c) 2 `((n+2)/r)`

D

d) `((n+2)/r)`

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