What type of epidemiological study involves comparing individuals with a disease to those without the disease?

Correct Answer: C

Rationale: Case-control studies (C) compare diseased (cases) and non-diseased (controls) to assess past exposures. A measures prevalence, B follows exposure, D tests interventions.

Correct Answer: D

Rationale: Attrition bias (D) arises from differential loss to follow-up affecting results (e.g., in cohorts). A is selection, B is data error, C is recall.

Correct Answer: B

Rationale: Descriptive studies (B) describe disease patterns (e.g., who, where, when). A and C are analytical, D is clinical.

Correct Answer: B

Rationale: Matching (B) reduces confounding (e.g., age-matching) in case-control studies. A, C, and D are incorrect or unrelated.

Correct Answer: B

Rationale: Case-control studies (B) suit rare diseases (e.g., mesothelioma) by focusing on cases. A, C, and D are less efficient.