Which statement is an example of begging the question?

The correct choice illustrates the logical fallacy known as "begging the question," which occurs when the conclusion of an argument is assumed in the premise, essentially arguing in a circle without providing any actual evidence. In the statement "I'm the best because I'm the greatest," the assertion of being the 'best' is directly tied to the claim of being the 'greatest,' but no independent justification is given to support why that claim is valid. The reasoning does not advance beyond the initial assertion; it merely restates the conclusion as if it were proven, failing to provide any rationale for why it should be accepted.

Each of the other statements does not exhibit this same fallacy. One speaks to the credibility of a person as a source without circular reasoning, another offers a reason to trust an opinion based on presumed expertise, and the last one presents a correlation about diet and health without assuming the truth of its conclusion in its premise.