What Is the Ultimate Fate of an Isolated White Dwarf

What is the ultimate fate of an isolated white dwarf?

A) It will cool down and become a cold black dwarf.
B) As gravity overwhelms the electron degeneracy pressure, it will explode as a nova.
C) As gravity overwhelms the electron degeneracy pressure, it will explode as a supernova.
D) As gravity overwhelms the electron degeneracy pressure, it will become a neutron star.
E) The electron degeneracy pressure slowly overwhelms gravity and the white dwarf evaporates.