The correct answer is B. The people were unfriendly and suspected anything that entered their territory to be an enemy.
Explanation:
The short story "The Gun" by the American writer Philip Kindred narrates the way in which a group of space explorers discovers a deserted planet and while trying to explore it, they are shot by a gun which is programmed to shot be the anything and anyone that arrives to the planet. During the story the explores also find out the planet used to be the home of an ancient civilization, but they are unable to know why the civilization disappeared. In the excerpt presented one of the characters is wondering about this explanation, and tells the others the inhabitants of this planet could have fought against each other considering they had a gun that shot everyone that approach to the planet which show they were unable to trust other and were not friendly as they even attacked other human beings. Thus, this excerpt shows the people that lived on the planet "were unfriendly and suspected anything that entered their territory to be an enemy" as they created a weapon to attack anybody who entered without proving they were enemies or not.