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: Esters can be obtained from carboxylic acids and alcohols, by applying the Fischer esterification reaction in which: 
 Options:  <1> A base is used as a catalyst. <2> A ketone is used as the solvent. <3> A reducing reagent is used. <4> An oxidizing agent is used. <5> Acid catalysis is used.
Example Output: 5

Example Input: Question: The simultaneous expression of IgM and IgD is observed for the first time in lymphocytes: 
 Options:  <1> Early Pro-B. <2> B mature. <3> Late Pro-B. <4> Pre-B. <5> B immature
Example Output: 2

Example Input: Question: A 65-year-old man with a history of pancreatic cancer undergoing chemotherapy. Emergency consultation for pain and edema of the entire lower limb from the groin. Which diagnostic test is more cost-effective to confirm the diagnostic suspicion? 
 Options:  <1> Dimer D. <2> Magnetic resonance. <3> Phlebography <4> Venous Doppler ultrasound. <5> Helical CT
Example Output:
4