Subject Based Registration is the option of allowing the student to do the registration by chosing the subjects of their choice. based on the amount of money that are fixed earlier for each subject of the elective groups.
This can be quite handy to the users while they come across scenarios like this.
And suppose if the student chooses only 2 out of 3 which was the minimum number of electives required.
Then the total cost would be $ 200.