(B) Secondary
The picture shows cars being manufactured by workers and transported for sale — this is manufacturing/industrial activity, which belongs to the Secondary sector.
The Secondary sector includes all activities that involve processing or manufacturing of natural/raw materials into finished goods (e.g., making cars, steel, cloth). Since the image shows manufactured goods (cars) being prepared for export, it is clearly a Secondary sector activity — not Primary (which involves natural production like farming) or Tertiary (which involves services).