Question

Which of these definitions fits the underlined word as it is used in this sentence? When American settlers reached the frontier, they found that it was already inhabited by Native American tribes. The territory at the farthest extent of a country's settled areas The limits of knowledge in a field like genetics or physics Sad, heart-wrenching Kind or category

Answer 1

Which word was underlined? i assume "Sad, Heart-wrenching, Kind or Category" are the answer choices 

Answer 2

the answer is "The Territory at the farthest extent of a country's settled areas."