Which of the following lines are legal and which are illegal? The class Undergraduate is a derived class of Student, and Student is a derived class of Person. a. Person p1 = new Student(); b. Person...

Which of the following lines are legal and which are illegal? The class

Undergraduate is a derived class of Student, and Student is a derived

class of Person.

a. Person p1 = new Student();

b. Person p2 = new Undergraduate();

c. Student s1 = new Person();

d. Student s2 = new Undergraduate();

e. Undergraduate ug1 = new Person();

f. Undergraduate ug2 = new Student();

g. Object ob = new Student();

h. Student s3 = new Object();