John, a 78-Year-Old Male Patient in a Hospital, Is Referred

John, a 78-year-old male patient in a hospital, is referred to a pulmonary specialist for a consult on his breathing problems. The specialist orders a CT scan of the lungs and is alerted by the electronic health record that a CT scan was performed 1 week ago. This alert is designed to prevent duplicate testing and is part of which essential electronic health record component?

A) Decision support system
B) Cost savings function
C) Physician assist system
D) Testing management system