**Core Concept**
Alkaline douch solutions for the nasal cavity typically contain a mixture of sodium salts and water, designed to provide a soothing, pH-balanced environment for the nasal mucosa. These solutions often include ingredients that help to stabilize the pH and reduce inflammation.

**Why the Correct Answer is Right**
Glucose is not a typical component of alkaline douch solutions for the nose. The primary purpose of these solutions is to provide a pH-balanced environment, reduce inflammation, and moisturize the nasal mucosa. Glucose, a simple sugar, is not relevant to these objectives and would not be included in an alkaline douch solution.

**Why Each Wrong Option is Incorrect**
**Option A:** NaCl (sodium chloride) is actually a common ingredient in saline solutions, including those used for nasal irrigation. It helps to maintain the pH balance and provides a gentle, non-irritating environment for the nasal mucosa.
**Option B:** Na biborate (sodium biborate) is indeed used in some nasal douch solutions, particularly those designed to provide a more alkaline pH. It helps to stabilize the pH and reduce inflammation.
**Option C:** NaHCO3 (sodium bicarbonate) is also commonly used in alkaline douch solutions for the nose. It helps to maintain a pH-balanced environment and reduce inflammation.

**Clinical Pearl / High-Yield Fact**
When selecting a nasal douch solution, it's essential to choose one that is pH-balanced and suitable for your specific needs. Alkaline douch solutions can be helpful for reducing inflammation and moisturizing the nasal mucosa, but they may not be suitable for everyone, particularly those with sensitive nasal passages.

**✓ Correct Answer: D. Glucose**