Final answer:
Motorcycles and motor driven cycles must be inspected by a designated authority or agency, which is responsible for ensuring compliance with safety and emissions standards. The correct option is D.
Step-by-step explanation:
The question pertains to the inspection of motorcycles and motor driven cycles. The correct answer to the question 'All motorcycles and motor driven cycles must be inspected by who?' is D) Designated authority or agency.
This means that a specific body, typically established by government or state regulation, is responsible for inspecting these vehicles to ensure they meet safety and emissions standards before they can be legally operated on public roads.
The inspection process is key to ensuring that all vehicles on the road are safe and that their emissions do not exceed prescribed limits. The correct option is D.