Written Records Document the Historic Past

Written records document the historic past. So why do archaeologists do historical archaeology?

A) Documentary sources can be selective and biased toward the interests of particular cultural, political, or ethnic groups.
B) Documentary sources do not exist for most of the historic past.
C) Archaeological excavations can demonstrate that historical records are wrong, and thus useless for inferring anything about the past.
D) None of the answers; if written records exist, archaeologists do not bother with historical archaeology.