challenge: What was the engine configuration of the Heinkel P.1073 project in 1944?
  
  A. One Heinkel HeS 011 turbojet and one BMW 003 axial-flow turbojet
  B. One Heinkel HeS 011 turbojet and one radial piston engine
  C. Two BMW 003 axial-flow turbojets
  D. Two Heinkel HeS 011 axial-flow turbojets
  Answer: 