The three correct answers for how in-text citations are formatted in MLA style are:
A. inside the closing period
B. in parentheses
E. outside the closing period
(Note: While technically "inside the closing period" and "outside the closing period" could be confusing, in MLA style, the citation is indeed within the sentence, right before the closing period of the sentence, which could be interpreted as "inside" as well.)
However, for clarity: the citation is within the sentence right before the period, so the best choices are B and A if considering standard phrasing. C and D are incorrect as in-text citations are not placed at the end of a paragraph or formatted in brackets. F is also misleading since while the citation appears at the end of a sentence, it's considered part of the sentence structure as well, not a standalone action.