How Do We Know That Folsom Hunters Camped at the Agate

How do we know that Folsom hunters camped at the Agate Basin site in the spring?

A) Coprolites from the site contain plant and small animal remains that are only present in the area in the springtime.
B) Bison tooth eruption patterns indicate the presence of juvenile bison that died in late March or early April.
C) Palynological data from the site indicate the presence of plant species that only pollinate in the spring.
D) Macrobotanical remains from the site indicate the presence of plant species that only grow in the spring.