**Core Concept**
Eutectic lignocaine–prilocaine is a topical anesthetic agent that combines the properties of lignocaine and prilocaine to provide effective pain relief. The unique property of this combination is related to its melting point and the way it interacts with the skin.

**Why the Correct Answer is Right**
The eutectic mixture of lignocaine and prilocaine has a lower melting point than either of its individual components. This allows it to penetrate the skin more easily, providing rapid and effective pain relief. The eutectic mixture also has a higher concentration of prilocaine, which helps to reduce the risk of methemoglobinemia, a condition that can occur with high doses of lignocaine.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not describe the unique property of eutectic lignocaine–prilocaine.

**Option B:** This option is incorrect because it is a side effect of lignocaine, not a unique property of the eutectic mixture.

**Option C:** This option is incorrect because it is a characteristic of other topical anesthetics, not a unique property of eutectic lignocaine–prilocaine.

**Clinical Pearl / High-Yield Fact**
The eutectic mixture of lignocaine and prilocaine is often used to provide pain relief before minor surgical procedures, such as skin biopsies or injections. It is also used to treat painful conditions, such as neuropathic pain and mucositis.

**Correct Answer:** C.