Answer:
b. impromptu speech
Step-by-step explanation:
As the name suggest, impromptu speech is the speech given by someone to group of people as a result of the an unplanned situation. This speech is never drafted nor was it ever reflected on.
As a result of Juanita running late for class and remembering that she needs to talk to her students about visual communication means that she would adapt an impromptu speech for the address. This is as a result of the fact that she never planned for it (She has a lesson plans she would have followed)