Assume that we have four classes: person, Teacher, Student and phDStudent is a subclass of student. which of the following assignments are legal, and why or why not? person p$1=$ new Student$()$; person p$2=$ new phDStudent$()$; phdStudent phd$1=$ new Student$()$; Teacher t$1=$ new Person$()$; Student s$1=$ newphDStudent$()$; Suppose that we have the following legal declarations abd assignments; Person p$1=$ new Person$()$; person p$2=$ new person$()$; phDStudent phd$1=$ new phDStudent$()$; Teacher t$1=$ new Teacher$()$; Student s$1=$ new Student$()$; Based in those just mentioned, which of the following assignments are legal, and why or why not?