**Core Concept**
Cycloplegic agents are used to temporarily paralyze the ciliary muscles in the eye, preventing accommodation and allowing for accurate measurement of refractive errors in children. In pediatric patients, the preferred cycloplegic agent should have a rapid onset of action, minimal side effects, and be safe for long-term use.

**Why the Correct Answer is Right**
The preferred cycloplegic agent in a 1-year-old child is **cyclopentolate** (C). Cyclopentolate is a potent, short-acting anticholinergic agent that rapidly paralyzes the ciliary muscles, making it ideal for use in young children. It has a rapid onset of action within 10-30 minutes and a duration of effect of 24 hours, allowing for accurate measurement of refractive errors.

**Why Each Wrong Option is Incorrect**
* **Option A:** **Tropicamide** is another anticholinergic agent, but it has a shorter duration of action (4-6 hours) and may not be sufficient for long-term use in young children.
* **Option B:** **Atropine** is a more potent anticholinergic agent, but its prolonged duration of action (7-14 days) and potential side effects make it less suitable for use in young children.
* **Option D:** **Homatropine** is another anticholinergic agent, but it has a slower onset of action and a shorter duration of effect compared to cyclopentolate.

**Clinical Pearl / High-Yield Fact**
When using cycloplegic agents in pediatric patients, it's essential to perform a thorough examination of the eyes, including retinoscopy and refraction, to ensure accurate measurement of refractive errors.

**Correct Answer: C. Cyclopentolate**