47. The phrase "their contributions" in line 16 refers to the contributions of (A) social scientists (B) prehistoric cultures (C) historians (D) documentation and knowledge

48. The author mentions an excavation at the size of a hotel in Sacramento in order to give an example of (A) a building reconstruction project (B) the work of the earliest historical archaeologists (C) a finding that conflicts with written records (D) the kind of information that historians routinely examine