Correct Usage of Capital Letters
Names should be capitalized, so if you refer to the department by its “official” name, The Department of English, you should capitalize the first word and all subsequent “non-connecting” words (so not and, or, of, in, etc).
However, if you’re just describing the department, in your case, The English department, you should capitalize only the names, so English, Abc, etc.
To answer you question, I believe (1) and (3) are good.