Minimum flow of Type-I impression compound at mouth temperature is:

**Core Concept**
Type-I impression compound is a thermoplastic material used in dentistry for making impressions of the oral cavity. The minimum flow of this material is an essential property that determines its suitability for specific applications.

**Why the Correct Answer is Right**
The minimum flow of Type-I impression compound is typically around 1.5 mm when measured at mouth temperature (around 35°C to 37°C). This is because the material has a relatively low viscosity at this temperature, allowing it to flow and adapt to the oral cavity's contours. The flow of Type-I impression compound is a critical factor in achieving accurate impressions, as it enables the material to capture the fine details of the oral cavity.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because Type-I impression compound is not typically characterized by a low minimum flow. In fact, the minimum flow of Type-I impression compound is usually higher than that of other impression materials.
* **Option B:** This option is incorrect because the minimum flow of Type-I impression compound is not typically around 3 mm. While some impression materials may have a higher minimum flow, Type-I impression compound is generally designed to have a lower minimum flow.
* **Option C:** This option is incorrect because the minimum flow of Type-I impression compound is not typically around 0.5 mm. While some impression materials may have a lower minimum flow, Type-I impression compound is generally designed to have a higher minimum flow.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the minimum flow of Type-I impression compound can be affected by factors such as temperature, pressure, and the presence of moisture. Therefore, it's crucial to understand the material's properties and behavior in different conditions to achieve accurate impressions.

**Correct Answer:** C. 2 mm.