Answer: a) Classifying students based on academic merit or potential.
Step-by-step explanation:
Sorting is a techniques that is used for organizing and arranging the elements or components in a certain order .Elements are presented in the form of category ,systematic order, group etc while sorting according to subject or parameter .
According to the question, classification of student in groups based on their potential and excellence is a way of sorting. Students are being categorized into group on that particular parameter.
Other options are incorrect because improving education, opting classes and placing of students keep going inequalities are not a method of sorting .Thus, the correct option is option(a).