Which of the following most logically completes the argument?

The growing popularity of computer-based activities was widely predicted to result in a corresponding decline in television viewing. Recent studies have found that, in the United States, people who own computers watch, on average, significantly less television than people who do not own computers. In itself, however, this finding does very little to show that computer use tends to reduce television viewing time, since __________.

• Amany people who watch little or no television do not own a computer  
• Beven though most computer owners in the United States watch significantly less television than the national average, some computer owners watch far more television than the national average  
• Ccomputer owners in the United States predominantly belong to demographic groups that have long been known to spend less time watching television than the population as a whole does  
• Dmany computer owners in the United States have enough leisure time that spending significant amounts of time on the computer still leaves ample time for watching television  
• Emany people use their computers primarily for tasks such as correspondence that can be done more rapidly on the computer, and doing so leaves more leisure time for watching television