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'.

Example Input: Question: The tissue is avascular: 
 Options:  <1> Epithelial. <2> Conjunctive. <3> Osseous. <4> Muscular. <5> Nervous.
Example Output: 1

Example Input: Question: In the activation of the serum complement, the assembly of the Membrane Attack Complex begins with: 
 Options:  <1> C9 <2> C5b. <3> C3a. <4> C6 <5> C8.
Example Output: 2

Example Input: Question: The most abundant immunoglobulin isotype produced by plasma cells of mucosal-associated lymphoid tissue is: 
 Options:  <1> IgM <2> IgD. <3> IgG <4> IgA <5> IgE
Example Output:
4