Step 1:
Kautilya's Arthashastra contains an Adhikarana called:
\[
\boxed{\text{Kantakashodhana}}
\]
Hence, Assertion A is correct.
Step 2:
“Kantaka” means thorn or harmful element in society.
Step 3:
This section deals with suppression and punishment of criminals and anti-social elements.
Thus, Reason R correctly explains Assertion A.
Step 4:
Therefore:
\[
\boxed{\text{Both A and R are correct and R is the correct explanation of A}}
\]
Hence, the correct answer is:
\[
\boxed{\text{(1)}}
\]