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: Of the following pairs of surface molecules, what is used by the virgin T lymphocytes to extravasate to the lymph node? 
 Options:  <1> CCR7 and L-selectin. <2> VCAM and L-selectin. <3> CCR7 and ICAM-1. <4> CCR9 and L-selectin. <5> CCR4 and VCAM-1.
[EX A]: 1

[EX Q]: Question: The probability that a person free of a disease develops it during a period of time, corresponds to: 
 Options:  <1> Chance. <2> Prevalence <3> Specificity <4> Forecast. <5> Risk.
[EX A]: 5

[EX Q]: Question: Which of the following enzymes catalyzes a hydrolytic reaction ?: 
 Options:  <1> Lactate dehydrogenase. <2> Chymotrypsin <3> Fumarasa <4> Triose phosphate isomerase. <5> RNA polymerase
[EX A]:
2