What is the purpose of presenting a false dilemma in a speech? to convince the audience that there are limited options to convince the audience that an argument is flawed to provide the audience with several alternative examples to sway the audience to rush to an opinion without facts

The correct answer is A: To convince the audience that there limited options.  

The false dilemma is a fallacy of oversimplification that offers the auduence a limited number of choices available, most of times two. The argeuments that are used are fallacious because they turn a complex problem with a lot of elements into a simple choices. It usually uses an "either this" or "either that" language.

So presenting a false dilemma in a speech is used to:

convince the audience that there are limited options.

In this case an example could be a political speech in which the immigration problem is addressed. Experts in the subject analyse a lot of different factors that are related to it, showing it's benefits and it's problems as well as several possible solutions to them. A politician running for campaign seeking the vote of those against immigration will simplify this by presenting a false dilemma speech, showing that if immigration is not stopped an economic crisis will occur. The options are now limited and voters must choose between stopping immigration or enter to an economic crisis.

to convince americans of the importance of others.