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The number of ways in which three number...

The number of ways in which three numbers in A.P. can be selected from 1,2,3,.....,n is

A

`(n(n-2))/4` , when n is even

B

`1/4(n - 1)^2`, when n is odd

C

`(n(n-2))/2` , when n is even

D

None of these

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A, B
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