The fourth alternative is correct (D).
It is the omniscien narrator, or narrator in the third person.
There are several types of omniscient narrator, but we can say that they are so called because they know all aspects of the story and its characters. You can, for example, describe feelings and thoughts of the characters, as well as describe things that happen in two places or with two characters at the same time.
The narrator of this passage fits this description, he demonstrates knowledge of the behavior of the characters and describes the environment in detail.