Which of the Following Would Indicate a Diagnosis of Advanced

Which of the following would indicate a diagnosis of advanced COPD?
1) Arterial blood gases show low O₂ and high CO₂.
2) Arterial blood gases show high O₂ and low CO₂.
3) Pulmonary function tests show low flow of air on expiration.
4) Pulmonary function tests show low flow of air on inspiration.

A) 1, 3
B) 2, 4
C) 1, 4
D) 2, 3