K.D. Vaughn is a U.S. Air Force veteran and federal IT manager who holds CompTIA A+ and Security+, PMP, ITIL, Certified ScrumMaster, and AWS Cloud Practitioner. K.D. wrote A+ CITY: The Common-Sense CompTIA A+ Study Guide and builds practice tests for people leveling up through IT certifications. Every question is written from scratch. None come from brain dumps.