Angle of deviation `(delta)` by a prism (refractive index = `mu` and supposing the angle of prism A to be small) can be given by
A. `delta = (mu - 1) A`
B. `delta = (mu + 1) A`
C. `delta = (sin (A + delta)/(2))/(sin (A)/(2))`
D. `delta = (mu - 1)/(mu + 1) A`
