The number of automobile thefts has declined steadily during the past five years, and it is more likely now than it was five years ago that someone who steals a car will be convicted of the crime. Which one of the following, if true, most helps to explain the facts cited above? ['There are more adolescent car thieves now than there were five years ago, and the sentences given to young criminals tend to be far more lenient than those given to adult criminals.', 'An upsurge in home burglaries over the last five years has required police departments to divert limited resources to investigation of these cases.', 'Although there are fewer car thieves now than there were five years ago, the proportion of thieves who tend to abandon cars before their owners notice that they have been stolen has also decreased.', 'Car alarms are more common than they were five years ago, but their propensity to be triggered in the absence of any criminal activity has resulted in people generally ignoring them when they are triggered.']