**Core Concept**
The cardiologist is trying to determine if the antihypertensive drug has a statistically significant effect on systolic blood pressure in a group of patients. This involves comparing paired data points (before and after treatment) to assess the magnitude of change.

**Why the Correct Answer is Right**
To assess the statistical significance of the change in blood pressure, the cardiologist needs to use a paired test, as each patient serves as their own control. The most appropriate test is the **Wilcoxon Signed-Rank Test**, which is a non-parametric test used to compare two related samples or repeated measurements on a single sample to assess whether their population mean ranks differ. This test is preferred when the data are not normally distributed or when the sample size is small.

**Why Each Wrong Option is Incorrect**
* **Option A:** The **t-test** is not suitable for this scenario, as it assumes normal distribution and equal variances, which may not be the case with paired blood pressure measurements.
* **Option B:** The **Chi-Square Test** is used for categorical data and is not applicable to continuous data like blood pressure measurements.
* **Option C:** The **ANOVA (Analysis of Variance)** test is used for comparing means among three or more groups, which is not relevant in this scenario where we have paired data.

**Clinical Pearl / High-Yield Fact**
When analyzing paired data, it's essential to use a paired test, such as the Wilcoxon Signed-Rank Test, to account for the correlation between the measurements.

**Correct Answer: C. Wilcoxon Signed-Rank Test**