n identical cells, each of emf `epsilon` and internal resistance r, are joined in series to from a closed circuit. One cell a is joined with reversed polarity. The potentia difference across each cell, except A, is
A. `(2epsilon)/(n)`
B. `(n-1)/(n)epsilon`
C. `(n-2)/(n)epsilon`
D. `(2n)/(n-2)epsilon`