What Is the Ionization Energy of Singly-Ionized Helium, Which Has $27.2 \mathrm { eV }$

Multiple Choice

What is the ionization energy of singly-ionized helium, which has 2 protons?

A) $27.2 \mathrm { eV }$
B) $13.6 \mathrm { eV }$
C) $54.4 \mathrm { eV }$
D) $36.4 \mathrm { eV }$
E) $6.80 \mathrm { eV }$