**Core Concept**
The laryngeal mirror is a crucial tool in otolaryngology used for visualizing the larynx and pharynx. Before use, the mirror must be warmed to prevent thermal contraction of the airway tissues, which could lead to discomfort or even injury to the patient.

**Why the Correct Answer is Right**
Warming the laryngeal mirror is essential to prevent thermal shock, which occurs when a cold instrument is introduced into a warm environment. This can cause the airway tissues to contract, leading to potential complications. By warming the mirror, the temperature differential between the instrument and the airway tissues is minimized, reducing the risk of thermal shock.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not related to the warming of the laryngeal mirror.
**Option B:** This option is incorrect as it does not provide a valid method for warming the mirror.
**Option C:** This option is incorrect as it may not be effective in warming the mirror to a safe temperature.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the laryngeal mirror should be warmed to a temperature that is comfortable for the patient, usually around 37°C. This can be achieved by placing the mirror on the back of the hand or in a warm water bath for a few minutes.

**Correct Answer: D.**