**Core Concept**
Inspiratory stridor is a high-pitched sound heard during inspiration, indicating partial airway obstruction. This occurs due to the turbulent flow of air through a narrowed airway, which is often caused by an extrathoracic obstruction.

**Why the Correct Answer is Right**
Inspiratory stridor is typically associated with upper airway lesions, such as laryngitis, epiglottitis, or tumors. The obstruction is usually located above the glottis, which is the opening between the vocal cords. As the patient inhales, air passes through the narrowed airway, producing the characteristic high-pitched sound. The glottis is a critical area in the airway where the vocal cords meet, and any obstruction here can cause inspiratory stridor.

**Why Each Wrong Option is Incorrect**
**Option A:** Expiratory stridor is more commonly associated with lower airway lesions, such as tracheal stenosis or bronchial obstruction, which are typically located below the level of the carina.
**Option B:** Inspiratory and expiratory wheezes are characteristic of asthma, which involves a diffuse airway obstruction, not a localized lesion.
**Option C:** Inspiratory and expiratory crackles are indicative of pulmonary edema or interstitial lung disease, which are not typically associated with stridor.

**Clinical Pearl / High-Yield Fact**
Inspiratory stridor is a medical emergency, often requiring immediate intervention to secure the airway. Remember the "5 Ps" of airway obstruction: Position, Patency, Partial obstruction, Pressure, and Pulmonary function.

**Correct Answer:** C.