Patients with chronic lung disease and difficulty breathing often adapt to the high concentration of \[C{{O}_{2}}\] in their blood. The breathing centres stop responding to \[C{{O}_{2}}\] level. If such a patient has difficulty in breathing, medical personnel are reluctant to give the patient pure oxygen. Based on what you know about control of breathing why do you think this is the case?

• A. The patient's body would use the oxygen to make even more\[C{{O}_{2}}\].
• B. The oxygen would increase concentration of bicarbonate, altering pH.
• C. Increased oxygen in the blood might slow or stop breathing.
• D. The body is not used to the oxygen, and the patient would overdose.