Answer:
B). Experimental.
Step-by-step explanation:
'Experimental study' is characterized as the study pattern in which the researchers deliberately involve intervention or manipulation in the treatment group to observe its effect.
As per the given details, the scientists have employed an 'experimental research' pattern because the research group was divided into two groups 'control group' and 'experimental group' where the experimental group receives an intervention('instructed to continue with their exercise-less routine'). Then the results of the two groups were observed, examined, and analyzed. Hence, it exemplifies the 'experimental research' type.