Since the order of selection does not matter we will use combinations to solve this problem.
Total number of students = 20
Number of students to be selected = 4
We are to find the combinations of 20 objects taken 4 at a time. This can be expressed as 20C4
20C4 = 4845
Thus, there are 4845 ways to select the 4 students.
So, the correct option is D