A coin is resting on the bottom of an empty container. The container is then filled to the brim three times, each time with a different liquid. An observer (in air) is directly above the coin and looks down at it. With liquid A in the container, the apparent depth of the coin is 7 cm, with liquid B it is 6 cm, and with liquid C it is 5 cm. Rank the indices of refraction of the liquids in descending order (largest first).
(a) nA, nB, nC
(b) nA, nC, nB
(c) nC, nA, nB
(d) nC, nB, nA
(e) nB, nA, nC