a. cyanosis
b. increased airway resistance
c. hypercapnia
d. dyspnea
e. hypoxia I may be looking to far into this question. The best indication of ventilation (with out a doubt) is PaCO2 or carbon dioxide in the arterial blood. To much is hypercapnia or low ventilation. This is a blood test result.
Signs are what someone can SEE and symptoms are what someone can FEEL.
If you consider a blood test as a sign, then C is your answer.
If you do not consider a blood test a sign then A, cyanosis is your answer.
I hope I didn't confuse you. a. cyanosis a. cyanosis | 