instruction:
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:
Question: What is the maximum number of stereoisomers of an aldohexose? 
 Options:  <1> two. <2> Four. <3> 8 <4> 16 <5> 32
answer:
4


question:
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
answer:
3


question:
Question: Which of the following congenital heart diseases is NOT considered as heart disease that produces volume overload ?: 
 Options:  <1> Interauricular communication. <2> Ventricular communication. <3> Defects of the atrio-ventricular septum. <4> Coarctation of the aorta. <5> Persistent ductus arteriosus.
answer:

4