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: We want to study if Vitamin D can increase the incidence of breast cancer. In our area we have a population registry of cancer. To achieve our goal, all women diagnosed with breast cancer are selected from the register we have and each case pairs with two controls. What study design has been chosen? 
 Options:  <1> Prospective cohort study. <2> Cases and controls study. <3> Case-control study nested. <4> Retrospective cohort study. <5> Ecological study
Example Output: 3

Example Input: Question: The Merkel cells are: 
 Options:  <1> Secretors of neuropeptides and sensory. <2> Secretors of mucus. <3> Migratory <4> From Schwann. <5> Fibroblasts.
Example Output: 1

Example Input: Question: Question linked to image # 12 In the CT that is shown, the most likely diagnosis is: 
 Options:  <1> Polycystic kidney disease <2> Retroperitoneal mass. <3> Renal tuberculosis <4> Renal cystic neoplasia. <5> Obstructive uropathy.
Example Output:
5