**Core Concept**
Impression plaster is a dental material used to create accurate impressions of the oral cavity. It is a type of hydrocolloid material that hardens to form a durable, yet flexible, impression. The addition of potato starch to impression plaster is a key characteristic that distinguishes it from other types of hydrocolloid materials.

**Why the Correct Answer is Right**
The addition of potato starch to impression plaster serves several purposes. It acts as a filler material, increasing the volume of the plaster and reducing its cost. The starch also helps to improve the mechanical properties of the plaster, making it more durable and less prone to cracking. Furthermore, the starch helps to control the setting time of the plaster, allowing it to set more quickly and evenly.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the addition of potato starch, which is a key characteristic of this type of impression plaster.
**Option B:** This option is incorrect because it is a type of impression material that does not contain potato starch. Alginate impression material is a type of hydrocolloid material that is commonly used in dentistry.
**Option C:** This option is incorrect because it is a type of dental stone that is used for making casts, not impressions.

**Clinical Pearl / High-Yield Fact**
The addition of potato starch to impression plaster helps to improve its mechanical properties and control its setting time, making it a valuable material for creating accurate impressions of the oral cavity.

**Correct Answer:** C. ZOE (Zinc Oxide Eugenol) plaster containing potato starch is called Zinc Oxide Eugenol (ZOE) plaster.