Answer:
A) The developer must supply a comparator object belonging to a class that implements the Comparator interface
Explanation:
The comparator interface handles the ordering (sorting) of user-defined classes, it does this by comparing two different objects from different classes. The comparator interface works by accepting a method which extracts a key for sorting of a type say N, and returns a comparator that compares to N, it therefore compares the object (current one) with the specified one