Detailed Instructions: 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'.
See one example below:
Problem: Question: A 13-year-old girl is operated on due to Hirschsprung illness at 3 months of age. Which of the following tumors is more likely to be present?
Options: <1> Abdominal neuroblastoma <2> Wilms tumor <3> Mesoblastic nephroma <4> Familial thyroid medullary carcinoma.
Solution: 2
Explanation: The answer to the given question should be a tumor, therefore Wilms tumor is the correct answer for the given question.

Problem: Question: The determination of mercury by the cold vapor generation technique is based on the reduction of mercury in acid solution and the entrainment of the elemental mercury obtained to the absorption cell for analysis by atomic absorption. The most commonly used reducers are:
Options: <1> SnCl2, for inorganic mercury and Na BH4 for both organomercury compounds and inorganic mercury. <2> Citrate, both for inorganic mercury, and organomercuriales. <3> Glutathione, especially suitable for all mercury species. <4> CaH2, for organomercurials and KMnO4 for inorganic mercury. <5> Na2SO3, for all mercury species.
Solution:
1