Dual Nature Of Radiation And Matter

The work functions of Caesium \((\mathrm{Cs})\), potassium \((\mathrm{K})\) and Sodium (Na) are \(2.14 ~\mathrm{eV}, 2.30 ~\mathrm{eV}\) and \(2.75 ~\mathrm{eV}\) respectively. If incident electromagnetic radiation has an incident energy of \(2.20 ~\mathrm{eV}\), which of these photosensitive surfaces may emit photoelectrons?