A physical therapist assistant working in an outpatient clinic has been assigned a group exercise program with patients in phase III of their cardiac rehabilitation program. For this phase of rehabilitation, which of the following interventions is MOST appropriate?

A. Resistance exercises using less than 15 pounds when in a sitting position

B. Slowly performing active range of motion activities of the upper and lower extremities

C. Walking on a treadmill at 2 mph

D. Running on a treadmill at 5 mph