Consider scenarios A to F in which a ray of light traveling in material 1 is incident onto the interface with material For the scenarios in which total internal reflection is possible, rank the scenarios on the basis of the critical angle, the angle above which total internal reflection occurs. At this angle, the refracted ray is at 90 degrees from the normal.Rank from largest to smallest. To rank items as equivalent, overlap them.
n1water=1.33, n2air=1.00
n1diamond=2.42, n2air=1.00
n1diamond=2.42, n2water=1.33
n1benzene=1.50, n2water=1.33

Critical angle represent the angle at which the refracted ray is 90°, this angle is the smallest and if this angle is increase above this value; instead of refraction we will have total internal reflection. It occurs when light travels from an optically denser medium to an optically less dense medium.

n₁ sin i = n₂ sin r using Snell's law where i represent incidence angle and r represent refracted angle

n₁ sin C = n₂ sin 90°

C = sin⁻¹ ( n₂ / n₁)

for water and air

C = sin⁻¹ ( 1 / 1.33) = 48.75°

for diamond and air

C = sin⁻¹ ( 1 / 2.42 ) = 24.41°

for diamond and water

C= sin⁻¹ ( 1.33 / 2.42) = 33.33°

and benzene and water

C = sin⁻¹ ( 1.33 / 1.50) = 62.46°

ranking from largest to smallest : n1benzene=1.50, n2water=1.33, followed n1water=1.33, n2air=1.00, followed by n1diamond=2.42, n2water=1.33 and finally the smallest is n1diamond=2.42, n2air=1.00