Definition: In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Input: Question: In what units is usually expressed the coefficient of molar absorptivity? 
 Options:  <1> mL mol-1 cm. <2> L mol-1 cm-3. <3> Photons per mole. <4> M-1 cm-1. <5> It is dimensionless.
