Next to the statues and the head, the slab seems unimpressive at first glance. It is roughly the size of a tabletop—three feet nine inches long, two feet four and a half inches wide, and eleven inches thick. But many experts would say that this rather small piece of rock was more valuable than any of the larger objects in the room. For it is the famed Rosetta Stone, which gave nineteenth-century scholars their first key to the secrets of ancient Egypt. Which part of a strong argument is the final sentence of the excerpt?

the reason
the evidence
the claim
the counterclaim