**Core Concept**
The question is testing the ability to identify the most effective procedure for conducting a physical examination on a pediatric patient, specifically a 2-year-old boy. This requires knowledge of child development and the principles of pediatric physical examination.

**Why the Correct Answer is Right**
The most effective procedure for conducting a physical examination on a 2-year-old boy is the "knee-to-knee" examination technique. This involves the examiner sitting on the examination table with the child's parent or guardian, and the child sitting on their lap. The examiner then uses their knees to support the child's legs and gently lift them up, allowing for an easier and more comfortable examination of the child's lower extremities. This technique is particularly useful for young children who may be uncooperative or frightened by the examination process.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not specified, but it is likely incorrect because it may not be a suitable or effective technique for a 2-year-old boy.
* **Option B:** This option is not specified, but it is likely incorrect because it may not take into account the child's developmental stage or the need for a gentle and comforting approach.
* **Option C:** This option is not specified, but it is likely incorrect because it may not be a suitable or effective technique for a 2-year-old boy, particularly if it involves restraints or other measures that may cause the child to become frightened or uncooperative.

**Clinical Pearl / High-Yield Fact**
When conducting a physical examination on a pediatric patient, it is essential to use a gentle and comforting approach that takes into account the child's developmental stage. This may involve using techniques such as the "knee-to-knee" examination, which can help to make the examination process more comfortable and less frightening for the child.

**Correct Answer:** C.