The question below consists of a set of six labelled sentences. They are all sentences of the same paragraph but their order has been jumbled. Sentence D given below is the fourth sentence in the correct order. Arrange the other five sentences in their correct order to make a coherent paragraph and answer the questions that follow:

A: Since the distance, the rays travel change with the angle, as you look at the surface, different colours look bright from different viewing angles.

B: Security inks exploit the principle that causes the vivid and constantly changing colours of a film of oil on water.

C: When two rays of light meet each other after being reflected from the different surfaces, they have each travelled slightly different distances.

D: Because in light, an electromagnetic wave, the peaks, and troughs of each ray then interfere either constructively, to appear bright or destructively, to appear dim.

E: The key is that the light is bouncing off two surfaces, that of the oil and that of the water layer below it.

F: The distance between the two rays determines which wavelengths, and hence colours, interfere constructively and look bright.