The correct answer is A. Ethos and Logos
Step-by-step explanation:
The purpose of rhetoric is to use strategies to convince the audience. In the case of ethos, this relies on the reputation or prestige of individuals as this makes ideas to be credible. This technique is used in "a board-certified cardiologist with own twenty-five years of experience" because by mentioning the experience and profession of Dr. William Leu the author refers to his prestige and this would make the audience believe the findings of this doctor.
On the other hand, the use of logos implies the author uses logic or facts to explain an idea. This can be seen in "patients who eat whole foods and a diet low in sodium are 75 percent less likely" because the author uses percentages, which are derived from the use of logic and mathematics, and refers to proven facts.