Contraindications for Nitrous Oxide-Oxygen Analgesia Include

Contraindications for nitrous oxide-oxygen analgesia include:
1) breathing difficulties.
2) communication problems with the patient.
3) patient dislike of "laughing gas."
4) emotional instability.
5) hypertension.
6) early pregnancy.

A) 1, 2, 4, 5, 6
B) 1, 3, 4, 5, 6
C) 1, 2, 3, 4, 5
D) 1, 2, 3, 4, 6
E) All of the above