Assertion: There is a great variety of techniques in behaviour therapy. 

Reasoning: The skill of the therapist lies in conducting an accurate behavioural analysis and building a treatment package with the appropriate techniques.

Both Assertion (A) and reasoning (R) are correct and but R is not the correct explanation of A.

There is a great variety of techniques in behaviour therapy. The skill of the therapist lies in conducting an accurate behavioural analysis and building a treatment package with the appropriate techniques.