Final answer:
The nurse is seeking an experimental research study, which is characterized by a high level of control over variables and is often conducted in a lab setting.
Step-by-step explanation:
The nurse researcher is looking for a highly controlled study usually conducted in a laboratory setting. The correct answer is C. Experimental research. This type of research involves a significant degree of control over variables and is typically conducted in controlled environments such as labs. In an experimental study, researchers manipulate the independent variable to determine its effect on the dependent variable, using random assignment to conditions to control for other variables. This differentiates experimental studies from observational studies, where the researcher does not manipulate the independent variable but rather observes and measures naturally occurring phenomena.
In experimental research, it is common to have two groups: the experimental group that receives the intervention or treatment and the control group that does not. The aspirin example provided in the question is a perfect instance of an experimental study where the effects of aspirin on heart attack rates are being tested in a controlled manner.