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: Pneumothorax occurs as a result of the entry of air into: 
 Options:  <1> The interstitial space. <2> The pleural space. <3> The peribronchial space. <4> The pulmonary circulation. <5> The systemic circulation.
