How Do Insects Overcome the Inefficiency of Their Hemolymph Flow

How do insects overcome the inefficiency of their hemolymph flow in taking oxygen to their tissues?

A) Their bodies are tubular,thus increasing the body surface area where gaseous exchange takes place.
B) Their respiratory system consists of tracheae,which are tiny air tubes that take oxygen directly to the cells.
C) A countercurrent mechanism ensures that the maximum amount of oxygen is absorbed from the environment.
D) Insects have highly vascularized extensions of their body walls,called parapodia.