Vending machines, because each is just a word telling you that both were empty. Vending machines is what the whole sentence is based on.
The answer to this question is Imagery
The subject is “milk.” The prepositional phrase is “in the cup.” The verb is “is.”
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".
