This question is not complete. Its full version is:
Why is rhythm an important element in a speech?
a. Rhythm provides the audience with important evidence.
b. Rhythm makes the audience aware of the type of argument the speaker is making.
c. Rhythm provides an example of why the opposition is against the argument.
d. Rhythm keeps the attention of the audience.
The right option is D.
The rhythm helps the speech flow and "keeps the attention of the audience".
When delivering a speech, it is paramount that the speaker combines pauses and interruptions, and resorts to an accurate intonation depending on they are stress or weak syllables. For example, employing rhythm, the speaker signals changes between topics.
Speakers who do not manage the rhythm tend to be considered as boring.
