Read this excerpt from "Caline."
So she went; in a new cotonade, and her Sunday shoes; with a sacredly guarded scrawl that the flagman sent to his sister.

What does the phrase "sacredly guarded scrawl" mean?

1 a diary that she uses to write her adventures

2 a sacred book that she takes everywhere

3 an important letter that she carries carefully

4 a piece of writing that she wants to publish