**Core Concept**
Drowning is a preventable cause of death that occurs when the respiratory system is impaired by aspiration of water, leading to hypoxia. The type of drowning is classified based on the circumstances and the presence of water in the lungs.

**Why the Correct Answer is Right**
The commonest type of drowning is freshwater drowning. This occurs when a person inhales large amounts of freshwater, which enters the lungs and causes an inflammatory response. The high water content in freshwater leads to rapid swelling of the lungs, making it difficult for oxygen to reach the bloodstream. The lungs may become heavy and difficult to expand, leading to respiratory failure.

**Why Each Wrong Option is Incorrect**
* **Option A:** Saltwater drowning is a type of drowning that occurs when a person inhales large amounts of saltwater. While it is a serious condition, it is less common than freshwater drowning due to the smaller volume of water inhaled.
* **Option B:** Chemical drowning is a type of drowning that occurs when a person inhales large amounts of a chemical substance. This is a rare type of drowning and is not the most common type.
* **Option C:** Dry drowning is a type of drowning that occurs when a person experiences laryngospasm or bronchospasm without actual water entering the lungs. While it is a serious condition, it is not the most common type of drowning.

**Clinical Pearl / High-Yield Fact**
It is essential to note that drowning can occur in any body of water, including swimming pools, lakes, and oceans. The American Red Cross recommends learning CPR and first aid to increase the chances of survival in the event of a drowning.

**Correct Answer:** C.