During Mechanical Ventilation, Functional Residual Capacity Is Adequately Maintained When

During mechanical ventilation, functional residual capacity is adequately maintained when a chest radiograph reveals:

A) Lung inflation to the eighth posterior rib above the level of the diaphragm
B) Lung inflation to the ninth posterior rib above the level of the diaphragm
C) Lung inflation to the ninth anterior rib and below the level of the diaphragm
D) Lung inflation to the eighth and ninth posterior ribs above the level of the diaphragm