**Core Concept**
Case-control studies, also known as retrospective studies, are a type of observational study design used to investigate the association between a specific exposure and a particular outcome or disease. This study design is particularly useful for examining rare outcomes or outcomes with long latency periods.

**Why the Correct Answer is Right**
Case-control studies involve selecting participants based on the presence or absence of the outcome of interest (cases and controls, respectively) and then retrospectively assessing their exposure to potential risk factors. This approach allows researchers to identify potential risk factors or associations that may not be feasible to study through other means. For instance, in a case-control study examining the relationship between a specific medication and an increased risk of a rare side effect, researchers would compare the frequency of exposure to the medication in individuals with the side effect (cases) versus those without (controls).

**Why Each Wrong Option is Incorrect**
**Option A:** Case-control studies are not typically used for hypothesis testing or determining causality, which is a key limitation of this study design.
**Option B:** While case-control studies can be used to identify potential risk factors, they are not the best design for establishing temporal relationships between exposure and outcome.
**Option C:** Case-control studies are not primarily used for evaluating the efficacy of interventions, as they are observational in nature.

**Clinical Pearl / High-Yield Fact**
A key limitation of case-control studies is the potential for recall bias, where participants may inaccurately report their exposure history due to the knowledge of their disease status.

**Correct Answer: C. Case-control studies are used for investigating associations between exposures and outcomes, particularly for rare or long-latency outcomes.**