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: The number of nodes of the LUMO (unoccupied orbital of lower energy) of 1,3-butadiene is: 
 Options:  <1> None. <2> One. <3> Two. <4> Three. <5> Four.
