Examine the definition of medical device. Medical devices are instruments, equipment, apparatus, in vitro diagnostic reagents and calibrators, materials, and other similar or related items used directly or indirectly in the human body, including required computer software, the utility of which is obtained primarily by physical and other means, not by pharmacological, immunological, or metabolic means, or which, although involved in these means, play only a secondary role. Note that the various options are split based on this definition, and take care to appreciate this propositional approach.