During a speech, especially to a large group or crowd, it is essential that the visual aid not only convey the message to the listener but should first catch the attention of the audience. Among the given choices, the best illustration that would fit with the presentation of the artistic style of Diego Rivera is the "slideshow of his most famous work".
Backyard gardens seems a bit broad whereas the rest focus in on a certain subject relating to gardens.
The best answer would be C) Mattru Jong.
