The information for a proposed college course is given below: Fee charged per student: $\$100$ Variable cost for each student: $\$20$ Overall fixed cost for the course: $\$480$ The expected number of students is 10. However, if the fee is lower, 20 students are expected to join the course. By how much must the course fee of $\$100$ be lowered in order to make the total profit from 10 students the same as the total profit from 20 students?
- A$\$16$
- B$\$24$
- C$\$40$
- D$\$50$