21.请阅读Passage 1,完成第1~5小题。 　　Passage 1 　　There a

[单选题]21.请阅读Passage 1,完成第1~5小题。 　　Passage 1 　　There are two kinds of motive for engaging in any activity:internal and instrumental.If ascientist conducts research because she wants to discover important facts about the world,that'san internal motive,since discovering facts is inherently related to the activity of research.If sheconducts research because she wants to achieve scholarly renown,that's an instrumental motive,since the relation between fame and research is not so inherent.Often,people have both for doingthings. 　　What mix of motives-internal or instrumental or both-is most conducive to success? Youmight suppose that a scientist motivated by a desire to discover facts and by a desire to achieverenown will do better work than a scientist motivated by just one of those desires.Surely twomotives are better than one.But as we and our colleagues argue in a paper newly published in theProceedings of the National Academy of Sciences,instrumental motives are not always an asset andcan actually be counterproductive to success. 　　We analyzed data drawn from 11,320 cadetsin nine entering classes at the United StatesMilitary Academy at West Point,all of whom rated how much each of a set of motives influencedtheir decision to attend the academy.The motives included things like a desire to get a good job laterin life and a desire to be trained as a leader in the United States Army. 　　How did the cadets fare,years later? How did their progress relate to their original motives forattending West Point? 　　We found,unsurprisingly,that the stronger their internal reasons were to attend West Point,themore likely cadets were to graduate and become commissioned officers.Also unsurprisingly,cadetswith internal motives did better in the military (as evidenced by early promotion recommendations)than did those without internal motives and were also more likely to stay in the military after theirfive years ofmandatory service. 　　Remarkably,cadets with strong internal and strong instrumental motives for attending WestPoint performed worse on every measure than did those with strong internal motives but weakinstrumental ones.They were less likely to graduate,less outstanding as military officers and lesscommitted to staying in the military. 　　Our study suggests that efforts should be made to structure activities so that instrumental consequences do not become motives.Helping people focus on the meaning and impact of theirwork,rather than on,say,the financial returns it will bring,may be the best way to improve not onlythe quality oftheir work but also their financial success. 　　There is a temptation among educators and instructors to use whatever motivational tools areavailable to recruit participants or improve performance.If the desire for military excellence andservice to country fails to attract all the recruits that the Army needs,then perhaps appeals to “moneyfor college,”“career training”or“seeing the world”will do the job.While this strategy may luremore recruits,it may also yield worse soldiers.Similarly,for students uninterested in learning,financial incentives for good attendance or pizza parties for high performance may prompt them toparticipate,but it may result in less well-educated students.

Which ofthe following is closest in meaning to the underlined word “cadets” in Paragraph 3?

A. In-service soldiers.
B. Military researchers.
C. Military officers.
D. Military trainees.