In a biprism experiment, the wavelenght of red light used is 6850Å and that of violet light used is 4050Å. The value of n for which the `(n+2)^(th)` bright band for violet light would correponded to the `n^(th)` bright band for red light for the same setting is
A. 3
B. 2
C. `2.5`
D. 4