Archaeologists Know That Folsom Points Date to Between 10,300 and 10,900

Archaeologists know that Folsom points date to between 10,300 and 10,900 radiocarbon years ago. If an archaeologist finds a Folsom point in a site, and assumes that the site dates to between 10,300 and 10,900 years ago, the archaeologist is using which of the following in his or her reasoning?

A) Seriation
B) Trapped charge dating
C) Relative dating
D) The index fossil concept