Which is a method of artificial respiration?

A method of artificial respiration involves techniques designed to enable an individual to breathe when they are unable to do so themselves. Each of the listed options demonstrates a valid way to provide artificial respiration:

Mouth-to-mouth refers to the technique where one person breathes into another person's mouth to provide air, allowing for oxygen delivery into the lungs. This method is widely recognized and frequently used in emergency situations.

Backpressure arm-lift is a technique where the rescuer uses their arms to help expel air from the lungs (when given in conjunction with breaths), creating back-pressure that aids in ventilation.

Mouth-to-nose involves breathing directly into the person's nose, which may be necessary in some circumstances, particularly if the mouth is injured or obstructed.

Since all these methods are established and recognized techniques for performing artificial respiration, the comprehensive answer encompasses all of them. By considering all options collectively, it illustrates a broad understanding of various artificial respiration techniques that can be applied in emergency situations.