<Tr> <Th> P O </Th> <Td> Alveolar oxygen tension, or partial pressure </Td> </Tr> <Tr> <Th> P CO </Th> <Td> Arterial carbon dioxide tension, or partial pressure </Td> </Tr> <Tr> <Th> P CO </Th> <Td> Alveolar carbon dioxide tension, or partial pressure </Td> </Tr> <Tr> <Th> P O </Th> <Td> Oxygen tension of mixed venous blood </Td> </Tr>

Which is the best definition of anatomical dead space