A well written essay should be unified; _____ The first requirement for unity is that the main idea should be clear. The second requirement is that there are no unrelated parts.
A) the selection of an interesting subject is therefore of vital importance.
B) even so, essays may vary considerably in length.
C) that is, everything in it should be related to the main idea.
D) in fact most essays are carefully planned.
E) essay competitions have recently become quite popular.
