根据下列内容，回答186-190题。
Five years ago, David Smith wore an expensive suit to work every day."1 was a clothes ad-dict," he jokes,"I used to carry a fresh suit to work with me so I could change if my clothes gotwrinkled." Today David wears casual clothes--khaki pants and a sports shirt--to the office. Hehardly ever wears a necktie."I'm working harder than ever," David says,"and I need to feelcomfortable."
More and more companies are allowing their office workers to wear casual clothes to work. Inthe United States, the changes from formal to casual office wear have been slow. In the early1990s, many companies allowed their workers to wear casual clothes on Friday (but only on Fri-day). This became known as "dress-down Friday" or "casual Friday". "What started out as an ex-tra one-day-a-week benefit for workers has really become an everyday thing." said business adviserMaisly Jones.
Why have so many companies started allowing their workers to wear casual clothes? One rea-son is that it' s easier for a company to attract new workers if it has a casual dress code. "A lot of youngpeople don't want to dress up for work," says the owner of a software company, "so it's hardto hire people if you have a conservative dress code." Another reason is that people seem happierand more productive when they are wearing comfortable clothes. In a study made by Levi Straussand Company,85 percent of employers said that casual dress has a side effect on work. Supportersof casual office wear also say that a casual dress code helps them save money. "Suits are expensive,if you have to wear one every day," one person said,"For the same amount of money, you can buya lot more casual clothes."
David Smith refers to himself as having been "a clothes addict" because___________.

A.he often wore khaki pants and a sports shirt
B.he couldn't stand a clean appearance
C.he wanted his clothes to look tidy and clean all the time
D.he didn't want to spend much money on clothes