(单选题)13: Americans are pound of their variety and individuality, yet they love and respect few things more than a uniform, whether it is the uniform of an elevator operator or the uniform of a five-star general. Why are uniforms so popular in the United States? Among the arguments for uniforms, one of the first is that in the eyes of most people they look more professional than civilian（百姓的）clothes. People have become conditioned to expect superior quality from a man who wears a uniform. the television repairman who wears uniform tends to inspire more trust than one who appears in civilian clothes. Faith in the skill of a garage mechanic is increased by a uniform. What easier way is there for a nurse, a policeman, a barber, or a waiter to lose professional identity（身份）than to step out of uniform? Uniforms also have many practical benefits. They save on other clothes. They save on laundry bills. They are tax-deductible（可减税的）. They are often more comfortable and more durable than civilian clothes. Primary among the arguments against uniforms is their lack of variety and the consequent loss of individuality experienced by people who must wear them. Though there are many types of uniforms, the wearer of any particular type is generally stuck with it, without change, until retirement. When people look alike, they tend to think, speak, and act similarly, on the job at least. Uniforms also give rise to some practical problems. Though they are long-lasting, often their initial expense is greater than the cost of civilian clothes. Some uniforms are also expensive to maintain, requiring professional dry cleaning rather than the home laundering possible with many types of civilian clothes. Question:The chief function of a uniform is to ____.

A: provide practical benefits to the wearer

B: make the wearer catch the pubic eye

C: inspire the wearer’s confidence in himself

D: provide the wearer with a professional identity