Answer:
(D) She did not use language appropriately
Explanation:
Tami used slang in a formal meeting and introducing a person who holds a high level position. Tami was very inappropriate at word choice, it made her comment embarrassing, weak and inelegant. The event organizer told her that she should use more formal language next time because she didn't use language properly.
Formal language is the language we use in more formal situations, being marked by the use of the cultured norm.