[sourav106]

IMO A
Surrounds is used to show present tense
patchwork of green fields......surround
(A) surround the San Joaquin Valley town bustles with farm workers, many of them ---> Correct
(B) surrounds the San Joaquin Valley town bustles with farm workers, many of whom are ---> Surrounds incorrect, Bcoz referred to patchwork, Whom is incorrect too
(C) surround the San Joaquin Valley town bustles with farm workers, many of who are ---> Who usage is incorrect
(D) surround the San Joaquin Valley town bustle with farm workers, many of which --> Which is for things
(E) surrounds the San Joaquin Valley town bustles with farm workers, many are ---> Surrounds incorrect, Bcoz referred to patchwork