A cube contains 216 magnetic blocks. The number of students in one class is 28. If each student in this class makes a cube, the number of magnetic blocks that they would need is 28 x 216 = 6048
The number of students in the other class is 25. If each student in this class makes a cube, the number of magnetic blocks that they would need is 25 x 216 = 5400
Thus, the number of magnetic blocks that she needs for all students is
6048 + 5400 = 11448
Option D is correct