Study the following infromations carefully and answer these questions given below:

Of the five boys A, B. C. D and E two are good, one is poor and two are average in studies. Two of them study in post-graduate classes and three in under-graduate classes. One comes from a rich family, two from middle-class families and two from poor families. One of them is interested in music, two in acting and one in sports. Of those studying in under-graduate classes, two are average and one is poor in studies. Of the two boys interested in acting one is a post-graduate student. The one interested in music comes from a middle-class family. Both the boys interested in acting are not industrious. The two boys coming from middle-class families are average in studies and one of them is interested in acting. The boy interested in sports comes from a poor family, while the one interested in music is industrious. C is poor in studies inspite of being industrious. A comes from a rich family and is not industrious but good in studies. B is industrious and comes from a middle-class family.

Q: Name the boys studying in post-graduate classes?