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In a triangle `ABC`, if `(b+c) / 11 = (c+a) / 12 = (a+b) / 13` then ` cosA / l = cosB / m = cosC / n` where `l, m, n` are least positive integer. Find the value of `(l+m+n)`.

A

`(7)/(5)`

B

`(5)/(7)`

C

`(17)/(16)`

D

`(16)/(17)`

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The correct Answer is:
B
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