A class has 22 male students and 18 female students. During the holidays, $60 \%$ of the students in this class went to do community work. At a minimum, how many female students participated in this work?
(a) 1
(b) 2
(c) 4
(d) 6
(e) 8
The correct answer is (b).

The total number of students in this class is $22+18=40$, of which $60\%$ went to do community work, that is, $0.6 \times 40=24$. The minimum number of female students who participated in this work is obtained when the number of male students who participated is maximum, that is, when all 22 male students are involved in the work, leaving a minimum of two spots for the female students.