**Core Concept**
The interarch relationship refers to the spatial relationship between the maxilla and mandible. In the pre-dental stage, the primary concern is to assess the potential for proper alignment of the teeth and the overall occlusion. This relationship is crucial for evaluating the development and growth of the dentition.

**Why the Correct Answer is Right**
The correct assessment of interarch relationship in the pre-dental stage involves evaluating the position of the maxilla in relation to the mandible. This is typically done using the **Steiner analysis**, which involves measuring the position of the maxilla in three planes: sagittal, vertical, and horizontal. The analysis helps to determine if the maxilla is in a Class I, Class II, or Class III relationship with the mandible.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a method for evaluating the interarch relationship. The Steiner analysis is a widely accepted method for assessing the interarch relationship.
**Option B:** This option is incorrect because it does not provide a clear method for evaluating the interarch relationship. The Frankfort horizontal plane is used in cephalometric analysis, but it is not the primary method for assessing the interarch relationship.
**Option C:** This option is incorrect because it does not specify a method for evaluating the interarch relationship. The Bolton analysis is used to evaluate the size and shape of the dental arches, but it is not the primary method for assessing the interarch relationship.

**Clinical Pearl / High-Yield Fact**
In the pre-dental stage, a Class II interarch relationship can lead to a narrow maxillary dental arch and a high palatal vault, which can increase the risk of crowding and orthodontic treatment.

**Correct Answer:** C. Steiner analysis.