What does this excerpt reveal about the setting of the story? It is a work site with dangerous equipment.
It is a tourist destination with unfamiliar sights.
It is a more heavily populated town than Buck has ever seen.
It is a colder climate than Buck has ever experienced.

It is a colder climate than Buck has ever experienced.

Explanation:

Jack London's "The Call of The Wild," tells the story of a domesticated dog Buck who ended up being sold and then driven/ made to work in the Yukon areas. The story contains the adventures that Buck was driven to in his new atmosphere where he finally realizes his true nature.

The narrator describes Buck's first experience in the wild in the given excerpt. He mentions how "Buck's feet sank into a white mushy something very like mud. He sprang back with a snort..." and how this "puzzled him". At the same time, "the onlookers laughed uproariously", which adds to the fact that this must have been Buck's very first encounter with snow.

Thus, the correct answer is the fourth option.