Refer to the Above Diagram, Which Depicts Gas Exchange Between

Refer to the above diagram, which depicts gas exchange between water and the blood in a fish gill. The numbers represent percent saturation of O₂. What can you conclude from this diagram?

A) The fluid in tube AB flows from B to A.
B) Oxygen transfer is more efficient if the fluid in both tubes AB and CD stops moving during gas exchange.
C) The fluid in tube CD flows from D to C.
D) Tube AB represents the flow of blood and tube CD represents the flow of water.
E) The net direction of oxygen diffusion is from tube CD to tube AB.