A uniform chain of length `l` is placed on rough table with length `l//n` (where `n gt 1`) , hanging over the edge. If the chain just begins to slide off the table by itself from this position, the coefficient of friction between the chain and the table is
A. `(1)/(n)`
B. `(1)/(n-1)`
C. `(1)/(n+1)`
D. `(n-1)/(n+1)`
