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Problem 1 (20 points): a) What is recursion and why do we need a base case for recursive processing? b) Design and write code for a set of classes that define the employees of a hospital: doctor, nurse and surgeon. Include methods in each class that are named according to the services provided by that person and then print an appropriate message. Write down any assumption you make when writing your program. Create a main driver class to instantiate and exercise several of the classes