Let's consider each choice and find what's wrong in each of them.
(A) is wrong since the frequency of phase change has nothing to do with the frequency of visible light. Since two sources are coherent, the frequency of visible light determines the distance between interference lines on a screen, while the phase difference between two sources is just off-set. They are irrelevant to compare.
(B) is wrong since the frequency of phase change is

hertz, which is not intregral number of

(C) is wrong since the phase difference does not destroy pattern. The pattern is result of coherence.
(D) is wrong since monochromaticity of the sources is not destroyed. The phase change does not affect the frequency. Totally different matter.
Hence, the correct answer is (E). You can get this answer even though you are not positive about how the eye detects the frequency.
52 of 100 people got the right answer.