Answer:
D. whether it's too general or too specialized for his intended audience.
Step-by-step explanation:
This is the main factor that Marco has to consider when evaluating the relevance of a source he plans to use. When deciding how suitable a source is, Marco should think about the nature of the source. If the source is too far from the level of knowledge of his audience, it runs the risk of being too complex, or not very convincing. If that is the case, then it is better for Marco to use a different source.