ANSWER: CASE-CONTROL STUDY
EXPLANATION:
An epidemiology expert will make use of a Case-control Study for proper determination of association or linkage between the oil spill and the disease outbreak (arthritis).
Case-control Study provides an observational experiment between two existing groups (two reservoirs) differing in outcome (affected and not affected), they are highlighted and compared on the basis of a context (disease outbreak; arthritis).
However, the known group is regarded as the control group and it provides a substantial guide to the confirm the validity of other experimental groups in relation to the general context (outbreak of arthritis).
It would most likely be located in the base of the skull and the lower portion of the spine.
It can help you better understand your current credit position , and also help you detect any inaccurate or incomplete information.