The largest trade-book publisher in the United States has announced the creation of a new digital imprint division, under which it will publish about 20 purely digital works to be sold online as either electronic books or downloadable copies that can be printed upon purchase.

A. works to be sold online as either electronic books or
B. works to sell them online, either as electronic books or
C. works and it will sell them online as either electronic books or as
D. works, and selling them online as either electronic books or as
E. works, and it will sell them online either as electronic books or

This question is testing the proper use of the idiom "either....or" and also the proper use of conjunction.

A - The publisher will publish 20 digital works to be sold online (conveys the meaning & is the correct usage of the infinitive). Also, "as" is used to connect the 2 clauses. Nothing wrong with this statement.
B - "either as .... or as" is expected.
C - The pronoun "it" references what? Pronoun ambiguity error.
D - wordy & awkward construction
E - Pronoun ambiguity error & "either as .... or as" is expected.