A recent study has revealed that the use of a new anti-theft device in

A recent study has revealed that the use of a new anti-theft device in cars has reduced the number of stolen vehicles by 15% in the last year. The device works by disabling the ignition system when it detects an unauthorized attempt to start the car. Law enforcement officials credit the decrease in thefts largely to the widespread adoption of this device. However, some skeptics argue that the reduction in car thefts could also be attributed to an increase in fuel prices over the same period, which they suggest might have made the operation of stolen vehicles more expensive and thus less appealing to thieves.

Which of the following, if true, would most strengthen the law enforcement officials' attribution of the reduction in car thefts to the new anti-theft device?

A) Other anti-theft measures, such as improved car alarms and tracking systems, have not been shown to significantly reduce car thefts when used alone.

B) The number of attempted car thefts that failed due to the anti-theft device was higher than the number of successful thefts of cars not equipped with the device.

C) Fuel prices had been steadily increasing for several years prior to the introduction of the new anti-theft device, with no corresponding decrease in car thefts until last year.

D) The new anti-theft device is inexpensive and has been installed in a wide variety of car models, including those that are most frequently stolen.

E) In areas where the new anti-theft device has been installed in fewer cars, the reduction in car thefts has been significantly smaller than in areas with higher adoption rates of the device.