Answer:
A sidebar
Explanation:
A sidebar because it is helpful when trying to find related information, or it may contain navigation tools making it easier to navigate through the webpage.
Firstly, it should be appropriated to define "supporting evidence". It is the evidence provided to support the main idea. It proves a point to keep the reader attention. So it this case, it might be said that the supporting evidence is the first option "man is blinded by his own vanity". It provides a "shocking idea" to prove a point and then an example is given to support this evidence.
