Answer
d.
Work Step by Step
Deadlock in this scenario arises when one student has obtained permission from the instructor and the other has paid the fee, but both are waiting for the remaining step to be completed by the other. By making the payment of the fee the sole requirement for entry, the deadlock is broken as the student who has paid the fee can enter the course, and the other student is denied entry. This eliminates the circular waiting condition, one of the necessary conditions for deadlock.
