Which three key documents are used to define the performance parameters and attributes of a system early in the Acquisition Life Cycle

A76-year old female with degenerative joint disease made an appointment with an orthopedic surgeon. the patient stated she has had severe pain in her right knee for six months. she has tried physical therapy and steroid injections but has not had any relief. the surgeon has agreed to schedule a right total knee arthroplasty (knee replacement).