While Trying to Discover the Nature of the Relationship Between

Multiple Choice

While trying to discover the nature of the relationship between stress and blood pressure, a researcher asks participants to complete a difficult task. The researcher monitors the participants' blood pressure while some are exposed to noisy distractions and others stay in a quiet environment. This type of research is a(n)

A) correlational study.
B) experiment.
C) case study.
D) placebo control study.