Step 1: Name and origin.
Systematic desensitisation (Joseph Wolpe) is a classic behaviour–therapy technique.
Step 2: Core steps.
(i) build an {anxiety hierarchy}; (ii) train {relaxation}; (iii) pair relaxation with {gradual imagined or in-vivo exposure} (counterconditioning).
Step 3: Eliminate distractors.
Psychoanalysis uses free association/interpretation; cognitive therapy uses cognitive restructuring—not SD.
Step 4: Conclude.
\[
\boxed{\text{Behaviour therapy (Option A).}}
\]