GMAT Sentence Correction (SC) | Re: An increasing number of schools are experimenting with looping classes

An increasing number of schools are experimenting with loopingclasses;that allows teachers to advance to the next grade level along with their pupils, to give students the opportunity to form long-term relationships with their instructors.


a)classes; that allows teachers to advance to the next grade level along with their pupils, to give

b)classes that allow teachers to advance to the next grade level along with their pupils and give

c)classes and allow teachers to advance to the next