**Core Concept**
The question is testing the understanding of different types of tonometers used in clinical practice, specifically their application surfaces. Tonometers are medical devices used to measure intraocular pressure (IOP) in the eye. The correct answer will be a type of tonometer that has a variation in its application surface.

**Why the Correct Answer is Right**
The correct answer is the **Goldmann Applanation Tonometer**. This tonometer uses a flat surface to apply a known force to the cornea, and the IOP is calculated based on the amount of applanation (flattening) of the cornea. The Goldmann Applanation Tonometer has a variation in its application surface, which allows for accurate measurement of IOP. The flat surface of the tonometer is in contact with the cornea, and the force applied is measured using a spring-loaded mechanism.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is likely referring to the **Schiotz Tonometer**, which uses a plunger to apply a known weight to the cornea. While it is a type of tonometer, it does not have a variation in its application surface like the Goldmann Applanation Tonometer.
* **Option B:** This option is likely referring to the **Rebound Tonometer**, which uses a rapid indentation of the cornea to estimate IOP. However, it does not have a variation in its application surface like the Goldmann Applanation Tonometer.
* **Option D:** This option is likely referring to the **Pascal Dynamic Contour Tonometer**, which uses a dynamic contour to measure IOP. While it is a type of tonometer, it does not have a variation in its application surface like the Goldmann Applanation Tonometer.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the Goldmann Applanation Tonometer is considered the gold standard for measuring IOP due to its high accuracy and precision. However, it requires a trained technician to operate, making it less accessible in some clinical settings.

**Correct Answer:** C.