What Is the Difference Between an Extrasolar Planet and a Sub-Brown

What is the difference between an extrasolar planet and a sub-brown dwarf?

A) There is no difference. These are two different names for the same object.
B) In its core a sub-brown dwarf generates a limited amount of energy through fusion of deuterium into helium. An extrasolar planet generates no fusion energy.
C) In its core a sub-brown dwarf generates a limited amount of energy through fusion of lithium into helium. An extrasolar planet generates no fusion energy.
D) An extrasolar planet orbits a star; a sub-brown dwarf does not. Otherwise, they are the same.