What Is the Binding Energy (In J/mol or KJ/mol) of an Electron

Multiple Choice

What is the binding energy (in J/mol or kJ/mol) of an electron in a metal whose threshold frequency for photoelectrons is 2.50 * 10¹⁴ /s

A) 2.75 * 10^-43 J/mol
B) 1.66 * 10^-19 J/mol
C) 1.20 * 10^-6 J/mol
D) 99.7 kJ/mol
E) 7.22 * 10¹⁷ kJ/mol