**Core Concept**
Congenital ptosis with poor elevation is a condition characterized by drooping eyelids present at birth, often associated with inadequate levator muscle function. The treatment aims to improve eyelid elevation and restore normal eyelid function.

**Why the Correct Answer is Right**
In cases of congenital ptosis with poor elevation, the primary goal is to restore eyelid function by addressing the underlying levator muscle weakness. **Blepharoplasty** with **frontalis sling** is a surgical procedure that involves creating a sling using a fascial or muscle graft to suspend the eyelid to the frontalis muscle. This procedure leverages the action of the frontalis muscle to elevate the eyelid, thereby improving eyelid function. The procedure is particularly effective in cases where the levator muscle function is poor.

**Why Each Wrong Option is Incorrect**
**Option A:** **Ptosis repair** alone is often insufficient in cases of congenital ptosis with poor elevation, as it may not adequately address the underlying levator muscle weakness.

**Option B:** **Blepharoplasty** without a frontalis sling is not sufficient to address the underlying levator muscle weakness and may not provide adequate eyelid elevation.

**Option C:** **Lid crutches** are a temporary measure used to support the eyelid, but they do not address the underlying levator muscle weakness and are not a suitable long-term solution.

**Clinical Pearl / High-Yield Fact**
In cases of congenital ptosis with poor elevation, a thorough assessment of the levator muscle function is essential to determine the most appropriate treatment approach.

**Correct Answer:** C.