Which of the following in not a cause of death due to suffocation

Suffocation is a general term used to indicate a form of asphyxia where entry of air to the lungs is prevented by any means other than pressure on the neck or drowning. Smothering is caused by closing the external respiratory orifices either by hand or by other means. Gagging is closing of mouth & nose by cloth or soft object & Chocking is caused by obstruction within airway. But throttling is an asphyxia produced by compression of the neck by human hands so it is by means of pressure on the neck. Ref: The synopsis of forensic medicine & Toxicology 28th edition pg: 185,188&189