Getting to know the people you'll be addressing-their background, interests, views, and familiarity with your topic-best describes which aspect of speaking:

a. research

b. observation

c. target audience

d. audience analysis

The correct answer is D. audience analysis.

Before you make a speech or a presentation on whichever topic, you need to get to know your audience. Depending on your audience, you will know what speech to make - whether it will be more formal, whether it will use a lot of terms, whether it will be easy or difficult to understand. So in order to do that, you need to do an analysis of your audience, so as to get familiar with them, their backgrounds, views, interests, etc.

the correct option is D

audience analysis

Getting to know the people you'll be addressing-their background, interests, views, and familiarity with your topic