Answer:
The drug legislation could have been successful despite the recent data, because (C) Illegal drug use in cities dropped sharply immediately after the legislation was implemented.
Step-by-step explanation:
The landmark drug legislation was introduced in Bedenia two years ago to combat the illegal drug use, meanwhile only in the past year there has been no major decrease in illegal drug use.
It means that in the first year after the legislation introduction it was successful and other factors have to be considered when analyzing why in the past year situation reversed. For example, it can be the spread in use of other drugs like extremely dangerous opioid fentanyl.