Which element in this passage tells the reader who the characters are?

The dialogue

Explanation:

The dialogue behind a lot of information about the characters and this helps the reader to know who they are, for example, through dialogue we know that Mrs. Lynde is a widow, is looking for a job and has experience in book-keeping. We also know that Nora is a friend of Mrs. Lynde, and Helmer is someone with influence to find a job for Mrs. Lynde.

use it to buy the fattest block of cheese