Answer:
Extemporaneous Style
Explanation:
Extemporaneous Style refers to the kind of style that is rehearsed but is delivered in a way that it seems spontaneous and flawless.
Kevin must adopt this style because he needs fact and figures to back his presentation regarding his advertising business. He should not come off as a slide reader for his own business. Therefore, this is the best style which would impress the investors greatly into giving his pitch a thought.