Christopher Colombus was most obviously the first explorer to route the straits off the tip of South America as the way to the east
C - Franks
Charlemagne was the ruler of the Frankish kingdom from 768-814. This gives you the answer that Charlemagne ruled only the Frankish kingdom, thus making all other answer choices incorrect.
Hope this helps!
Im not sure but I want to try to help you though so between B. Or C.
Answer:
A treaty that further expanded Rome
