Final answer:
The phrase that most supports the conclusion that this tale functions as an origin story is option C) "Hottah commanded Ithenhiela to fling the tree branch, from which grew a mighty forest."
Step-by-step explanation:
The phrase that most supports the conclusion that this tale functions as an origin story is option C) "Hottah commanded Ithenhiela to fling the tree branch, from which grew a mighty forest." This phrase suggests that Ithenhiela possesses supernatural powers and has the ability to create a forest from a tree branch. This showcases Ithenhiela's legendary status and establishes the tale as an origin story.