A – Wrong
Age is irrelevant.
B – Correct
The text states that an increase in use of cannabis can lead to psychotic illness. This statement provides an alternate link that those with psychotic illness can lead to them using cannabis.
C – Wrong
This statement suggests that the link made between use of cannabis and development of psychotic illness may not be valid. This is irrelevant to the question.
D – Wrong
This suggests that there may be more cannabis users than we think which is irrelevant to the question.