Which of these is an example of an idom

The correct word to complete the sentence

Read the excerpt from "the blackfeet creation." how do readers know that this excerpt is from a myth? the excerpt describes an animal called a muskrat. the excerpt describes old man drying the mud. the excerpt describes old man scattering mud over water. the excerpt describes how muskrat create land.

Based on this excerpt the authors are most likely to attempt to answer which question