Correct option is B
DBT is the first-line psychotherapy for borderline PD, focusing on mindfulness, distress tolerance, emotional regulation, and interpersonal effectiveness.
Explanation of options: (a) ✘ Supportive therapy may help but not primary evidence-based. (b) ✔ Correct; DBT specifically designed for borderline PD. (c) ✘ CBT helps mood disorders, less effective in borderline PD. (d) ✘ Psychoanalysis not practical in acute instability.