The delivery of a speech helps the audience understand the topic, what you're talking about, and keeps the speech on track.
For example, if you were giving a speech on Romeo and Juliet, you wouldn't want to get off topic by giving information about Shakespeare's life instead of information and analysis of the play.
The correct answer is "select the best solution". After evaluating possible solutions, that is considering the advantages and degree of effectiveness of each solution, the following step is to choose the most suitable solution. The other option refers to previous steps in the creative problem solving process
The verb is past participle so that would be option A.
