Which one of the following is a possibility for most of us in regards to breathing, by making a conscious effort

Options

A. The lungs can be made fully empty by forcefully breathing out all air from them
B. One can breathe out air totally with out oxygen
C. One can breathe outairthrougheustachian tubes by closing both the nose and the mouth
D. One can consciously breathe in and breathe out by movingthe-dfaphragm alone,without moving the ribs at all.

Answer

D