## **Core Concept**
The question revolves around genetic testing for a patient with a family history of dementia. Dementia can result from various genetic factors, and identifying the specific genetic cause can help in management and counseling. The primary types of genetic testing relevant here include **Whole Exome Sequencing (WES)**, **Whole Genome Sequencing (WGS)**, **Targeted Genetic Testing**, and **Genetic Screening**.

## **Why the Correct Answer is Right**
The correct answer, **Whole Exome Sequencing (WES)**, is a genetic testing method that focuses on the protein-coding regions of the genome, known as the exome. This approach is particularly useful for identifying genetic mutations that cause Mendelian disorders, such as certain forms of dementia (e.g., frontotemporal dementia, familial Alzheimer's disease). WES offers a good balance between cost, time, and diagnostic yield for patients with a strong family history of a genetic disorder.

## **Why Each Wrong Option is Incorrect**
- **Option A: Whole Genome Sequencing (WGS)**. While WGS provides comprehensive data on all parts of the genome, it is more expensive and generates more data that may not be immediately interpretable or relevant. It's not typically the first-line choice for targeted testing in familial dementia unless WES is inconclusive.
- **Option B: Targeted Genetic Testing**. This approach focuses on specific genes known to be associated with a particular condition. While useful, it might not be as comprehensive as WES if the causative gene is not known or if the condition is caused by a gene not included in the panel.
- **Option D: Genetic Screening**. This is a broad term that can refer to various types of testing aimed at identifying genetic risk factors. It is less specific than WES and might not offer the same level of detail in identifying causative mutations.

## **Clinical Pearl / High-Yield Fact**
For patients with a strong family history of dementia, **Whole Exome Sequencing (WES)** is often considered a valuable initial genetic test because it can simultaneously assess multiple genes associated with dementia. A key clinical pearl is that a positive genetic test result can guide management, facilitate genetic counseling for the patient and family members, and help in making informed decisions about preventive measures or therapeutic interventions.

## **Correct Answer: C. Whole Exome Sequencing.**