Answer:
A). Relevant historical facts.
Step-by-step explanation:
In the given excerpt, the author introduces the topic using 'relevant historical facts' which not only reveals the key idea or subject to the readers but also assists in capturing the readers' attention and establish the credibility of the author's argument. It is outlining the main points that are going to be dealt with and offers a precise summary of the text. Thus, option A is the correct answer.