Information about a collection of students is given by the relation studinfo (studid, name, sex). The relation enroll (studld, Courseld) gives which student has enrolled for (or taken) what course(s). Assume that every course is taken by at least one male and at least one female student. What does the following relational algebra expression represent?
pi courseld (( pi studlld ( sigma sex= female^ * (studlnfo))* pi courseld (enroll)) - enroll)
(a) Courses in which all the female students are enrolled
(b) Courses in which a proper subset of female students are enrolled
(c) Courses in which only male students are enrolled
(d) None of the above