What Is the Difference Between an Assignment and a Sublease

What is the difference between an assignment and a sublease with regard to unpaid rent?

A) Unlike a sublease,only the original tenant is liable in an assignment.
B) A landlord can sue in an assignment situation,but not in a sublease situation.
C) Unlike an assignment,both the lessee and sublessee are liable in a sublease.
D) In an assignment,both the assignee and assignor are liable to the landlord for failure to pay rent.With a sublease,only the original tenant is liable to the landlord.
E) There is no difference between an assignment and a sublease with regard to unpaid rent.