During laryngoscopy and endo-tracheal intubation which of the maneuver is not performed –: (A) Flexion of the neck, (B) Extension of Head at the atlanto-occipital joint, (C) The laryngoscope is lifted upwards levering over the upper incisors, (D) In a straight blade laryngoscope, the epiglottis is lifted by the tip
Answer is C. Upper incisor teeth have to be protected by a guard and the leverage of teeth should be avoided.

"Loose, filled or capped teeth, especially upper incisors, may be protected by a guard".

— Lee