Answer:
Possessive pronoun.
Step-by-step explanation:
A pronoun case in a sentence depends on the context or the way the pronoun is used in that sentence. This means that according to how a pronoun is used, we can determine what case it is.
In the given sentence "Amelia let Shana borrow her book", the pronoun "her" refers to Amelia. And in that context, the pronoun denotes the possessive nature of the book, meaning the book belongs to Amelia.
Thus, the pronoun case is a possessive pronoun.