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'.

[EX Q]: Question: Ferrous oxide, known as wustite (FeO) is non-stoichiometric because it contains: 
 Options:  <1> Excess iron <2> Oxygen excess <3> Iron defect. <4> Oxygen defect. <5> Defect of iron and oxygen.
[EX A]: 3

[EX Q]: Question: Transketolase catalyzes the transformation of ribose-5-phosphate and xylulose-5-phosphate into: 
 Options:  <1> Two molecules of ribulose-5-phosphate. <2> Sedoheptulose-7-phosphate and glyceraldehyde-3-phosphate. <3> Fructose-6-phosphate and erythrose-4-phosphate. <4> Glyceraldehyde-3-phosphate and glucose-6-phosphate. <5> 6-Phosphogluconate and glyceraldehyde-3-phosphate.
[EX A]: 2

[EX Q]: Question: The color of the eyes depends on the pigment present in: 
 Options:  <1> Pupil. <2> Cornea. <3> Iris. <4> Choroid <5> Retina.
[EX A]:
3