When electromagnetic radiation of wavelength $300 \, nm$ falls on the surface of a metal, electrons are emitted with a kinetic energy of $1.68 \times 10^5 \, J \, mol^{-1}$. What is the minimum energy (work function) needed to remove one mole of electrons from the metal? $(h = 6.626 \times 10^{-34} \, J \, s, c = 3 \times 10^8 \, m \, s^{-1}, N_A = 6.022 \times 10^{23} \, mol^{-1})$

• A
  $2.31 \times 10^6 \, J \, mol^{-1}$
• B
  $3.84 \times 10^4 \, J \, mol^{-1}$
• C
  $3.84 \times 10^{-19} \, J \, mol^{-1}$
• D
  $2.31 \times 10^5 \, J \, mol^{-1}$