Answer:
The indirect approach is the better choice.
Explanation:
Indirect refers to something that is not straight to the point or direct. It comes gradually and in a less quick way.
In this case, it can be understood that the audience is unsure about the speaker's credibility and needs evidence before it can accept it.
By taking a direct approach, the speaker would most likely scare the audience away and not gain credibility.
By taking an indirect approach, the speaker gradually proves his/ her points and can do so by reasoning with the audience and providing them with evidence, thus, slowly overcoming their reservations and setting his/ her credibility.