Respuesta :
C. facts and statistics from credible sources so they can know where you are getting your information and to make sure you aren't making things up or using unreliable resources such as Wikipedia
The correct answer is C. facts and statistics from credible sources.
A formal audience obviously requires a formal speech, so you would need to adjust your speech to cater to their needs. This means that you would need to use academic language, facts, quotations, anything that might help you support your presentation - however, those aids must be credible so as to avoid plagiarism/false facts.