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""^(n-2)C(r)+2""^(n-2)C(r-1)+""^(n-2)C(r...

`""^(n-2)C_(r)+2""^(n-2)C_(r-1)+""^(n-2)C_(r-2)` equals :

A

`""^(n+1)C_(r)`

B

`""^(n)C_(r)`

C

`""^(n)C_(r-1)`

D

`""^(n-1)C_(r)`

Text Solution

Verified by Experts

The correct Answer is:
B
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