2. (30 points) Assume the following classes are fully implemented (details omitted for simplicity). Assume the following code (which is crror free) is executed before each line of code given in parts a-j below (so treat each problem independently): Person p1 miew Studant(): Person p2= new phosisudent( (): Person p3= new person(): Person p4= new Teacher () : Bhostudent, phd = new phostudent, () : Teacher t1= new Teacherio: student s1= new student(); For each of the following, tell whether the statement is legal, will cause a compiler error, or will cause a runtime error, and briefly state why (if it is not legal). a. t1= new Person(); b. Object obj = pl; c. s1=( Student ) new Object ); d. s1=p2; e. double gna =p. getGPAO; f. double gpa = (Student) p2.getGPAO; g. boolean abd =(( PhDStudent ) p2 . isABD0; h. Ul giveGrade(phd1,1); i. p3.giveGrade(s1,1); j. ((Teacher) p4) girsGarade( (Student) (new PhDSTudenu)), 1)