You will be given a definition of a task first, then some input of the task.
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'.

Question: On a blood agar plate, a greenish or brown halo around a bacterial colony indicates that the bacteria produces: 
 Options:  <1> A siderophore. <2> α hemolysis. <3> Coagulase <4> β galactosidase. <5> Neutral metabolites
Output:
2