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'.

[Q]: Question: Which of the following covalent bonds does not appear in proteins ?: 
 Options:  <1> Phosphodiester linkage. <2> Amide link. <3> O-glucosidic bond. <4> Disulfide bond. <5> Hydrogen bond.
[A]: 1


[Q]: Question: The reovirus .: 
 Options:  <1> They are released from the cell by budding. <2> They replicate their genetic material in the cell nucleus. <3> They have a lipid envelope. <4> They form virions resistant to acid pH. <5> They are transmitted by blood.
[A]: 4


[Q]: Question: A primary standard solution in a titration should not: 
 Options:  <1> Be prepared from a high purity reagent. <2> Have an exactly known concentration. <3> Keep your composition over time. <4> React instantly. <5> Give rise to secondary reactions.
[A]:
5