How to put concentration on studies write 5 methods.

Train your brain. Playing certain types of games can help you get better at concentrating.
Get your game on. Brain games may not be the only type of game that can help improve concentration. ...
Improve sleep. ...
Make time for exercise. ...
Spend time in nature. ...

The purposes of learning about your audience, asking questions before presenting, and analyzing the diversity of your audience is to be able to:
c.  acknowledge controversy and ask for careful consideration
b.  tailor your speech to meet the audience's needs
a.  understand the  basic characteristics of the audience
therefore, the answer is option d. all of the above. all the options given are the purposes of learning about your audience.