**Core Concept**
The treatment of meningomyelocele involves surgical repair, but before surgery, the exposed neural placode must be protected from infection, trauma, and desiccation. A sterile dressing is applied to maintain a moist environment.

**Why the Correct Answer is Right**
The gauze should be soaked in saline solution to maintain a moist environment, preventing desiccation of the neural tissue. This is crucial because the neural placode is sensitive to drying, which can lead to further damage and potential infection.

**Why Each Wrong Option is Incorrect**
**Option A:** Hydrogen peroxide is not suitable for the dressing as it can cause tissue damage and is not sterile.
**Option B:** Betadine solution is an antiseptic, but it is not suitable for the initial dressing as it can cause tissue irritation and delay healing.
**Option C:** Glycerin can cause dehydration of the neural tissue, exacerbating the condition.

**Clinical Pearl / High-Yield Fact**
It is essential to maintain a moist environment around the exposed neural placode to prevent desiccation and promote healing.

**Correct Answer: D. Saline solution.**