What are common early signs of hypoxia in aircrew?

• A. Headache, dizziness, confusion, tachycardia, shortness of breath, visual disturbances
• B. Nausea, hair loss, joint stiffness, muffled hearing
• C. Cough, fever, rash, fatigue
• D. Leg pain, swollen ankles, blurred vision, weight gain

Answer: (A)