What is one common non-mail item a mail carrier might encounter?

A common non-mail item that a mail carrier might encounter is a package that is too large to fit in standard mailboxes. This situation is significant because when a package exceeds the dimensions of a typical mailbox, it cannot be delivered as intended. Instead, the mail carrier may need to leave a notice for the recipient or take the package back for further handling, depending on postal regulations. This situation can often lead to increased interactions with customers, as recipients will need to arrange for pick-up or alternative delivery options.

While other choices present scenarios involving mail-related items or issues, they are all related to the postal process and still fall under what can be considered "mail." In contrast, the situation of a package not fitting in a mailbox is a more physical limitation that directly affects the delivery process and is less about the mail itself. It emphasizes the logistical challenges mail carriers face beyond just the mail items they're delivering.