Pulmonary circulation is the key component that supports both respiratory and cardiovascular systems. Examine this diagram of a human heart as seen while looking at the front of the body.

*diagram would be pictured here, but is attached instead*

Which correctly identifies where the blood is flowing to and from?
A: lower body, B: left lung, C: right lung, D: upper body
A: upper body, B: right lung, C: left lung, D: lower body
A: right lung, B: upper body, C: lower body, D: left lung
A: left lung, B: lower body, C: upper body, D: right lung