Step 1: Idea: sort techniques by what they change
Behaviour therapy changes actions through learning. Cognitive therapy changes thinking. Sort each option into one of these.
Step 2: Token economy
Rewards for target actions. It changes actions, so it is behavioural.
Step 3: Cognitive restructuring
It replaces irrational beliefs with realistic ones. It changes thinking, so it is cognitive. This is the odd one.
Step 4: Modelling
Copying an observed model. It changes actions, so it is behavioural.
Step 5: Systematic desensitisation
Gradual exposure with relaxation. It changes the fear response, so it is behavioural.
Step 6: Conclusion
Only cognitive restructuring is outside behaviour therapy, because its target is the way a person thinks and not the way a person acts. So option (2) is the answer, and the other three are all standard behavioural tools.
Final Answer:
Option (2) is the answer.
\[ \boxed{\text{Option (2)}} \]