challenge: What is the primary difference between Volume CT and traditional CT in terms of x-ray detector orientation?
  
  A. Volume CT uses a single detector, while traditional CT uses multiple detectors
  B. Volume CT uses a circular detector, while traditional CT uses a square detector
  C. Volume CT uses a one-dimensional detector, while traditional CT uses a two-dimensional detector
  D. Volume CT uses a two-dimensional detector, while traditional CT uses a one-dimensional detector
  Answer: 