**Core Concept**
Impression compound is a thermoplastic material used in dentistry to create accurate impressions of the teeth and surrounding tissues. Before inserting the loaded tray, the temperature of the impression compound should be checked to ensure it is within a suitable range for optimal impression taking.

**Why the Correct Answer is Right**
The correct temperature range for impression compound is between 98°F and 104°F (36.7°C and 40°C). This temperature range allows for optimal flow and recovery of the impression compound, resulting in accurate and detailed impressions. If the temperature is too high, the compound may be too soft and difficult to handle, while a temperature that is too low may cause the compound to be too hard and brittle.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because there is no specific temperature range mentioned for this option. Impression compound temperature is a critical factor in impression taking.
**Option B:** Not applicable as this option is missing.
**Option C:** Incorrect because this temperature range is not suitable for impression compound. A temperature above 104°F (40°C) may cause the compound to become too soft and difficult to handle.

**Clinical Pearl / High-Yield Fact**
A temperature range of 98°F to 104°F (36.7°C to 40°C) is ideal for impression compound to ensure accurate and detailed impressions.

**Correct Answer: D.**