What Can Be Said About the Possibility of the Existence

What can be said about the possibility of the existence of the hydrogen isotope represented by the symbol shown below?

A) This isotope of hydrogen is not possible because it has no electrons.
B) This isotope of hydrogen is not possible because atoms of hydrogen have one proton.
C) This isotope of hydrogen is possible; it simply contains no protons and is an ion.
D) This isotope of hydrogen is possible; it simply contains no neutrons.
E) This isotope of hydrogen is possible; it simply has two neutrons.