The Employee base class and the derived classes Sales and Technician (their definitions and implementations) can be found in " Files Needed For Coursework Exam 2". Say we want to write a function that gives a raise to an employee, whatever the type of employee we are interested in (i.e. whether they are of the base class or of derived class types). We may write something like: void raise(Employee em1) \{ em1.giveRaise(); What symbol(s), if any, are missing from the header of this function? Select one: a. [] b. No change C. * d. 8