(A) Optical density of core should be greater than the optical density of cladding.
(B) r and θ will always be equal.
(C) Optical density of cladding is \(\frac{sinθ sin i}{sin r}\).
(D) Optical density of cladding is \(\frac{sin r sin i }{sin θ}.\)
Choose the correct answer from the options given below: