the rapid population growth within the boundaries of the Springfield Public School District was a source of concern for an overcrowded school system where the student enrolments of 70 percent of them are above the state board of education's suggested limits.
a) where the student enrolments of 70 percent of them are
b) where they have 70 percent of the student enrolments.
c) where 70 percent of the student enrolments are
d) which has 70 percent of the student enrolments
e) in which 70 percent of them have student enrolment
the correct answer is c but manhattan gmat prep says "where" can used to modify a noun place such as area, site , county and cannot modify metaphorical places such as condition, situation , case, circumstances and arrangements. in these cases, use in which rather than where