The correct answer is D.
Explanation:
In a parenthetical citation, the structure is (last name of the author, year), which is added at the end of the citation. Moreover, if there are three authors, as in this case, the first citation should include the last names of all of them. However, for the second, third, etc. citations, only include the first author and then the words et al. that indicate the work cited has other authors not mentioned.
In this context, the correct option is "demands, expects, and requires of students (Swan et al., 1995)" because this is the second citation, and therefore only the last name of the first author should be included; also, this is followed by the abbreviation et al. and finally by the year.