13.An optical fiber with index of refraction n = 1.25 is surrounded by air. The end of the fiber is polished to be flat and perpendicular to the length of the fiber. What is the maximum angle of incidence for the light ray such that it will be confined and transported by the optical fiber? (A) sin⁻¹(0.5) = 30° (B) sin⁻¹(0.6) = 37° (C) sin⁻¹(0.71) = 45° (D) sin⁻¹(0.75) ≈ 49° (E) sin⁻¹(0.8) ≈ 57°