challenge: When was the 3rd Maryland Cavalry Regiment mustered in for three-year service?
  
  A. January 9, 1864 - August 8, 1865
  B. August 8, 1862 - January 9, 1863
  C. December 9, 1864 - January 9, 1865
  D. August 8, 1863 - January 9, 1864
  Answer: 