Final answer:
The correct MLA citation among the provided options is D, which directly quotes and includes the title of the article in parentheses. This citation must match an entry on the Works Cited page to adhere to MLA standards.
Step-by-step explanation:
Diana is working on an expository essay related to food safety and needs to correctly cite evidence in MLA format. When citing information obtained from a source, MLA format often requires including the author's name and the page number in a parenthetical citation. However, in cases where no page number is available, which can occur with web resources, the title of the article or a shortened version can be used instead. Importantly, the in-text citation should be placed at the end of the sentence before the period, and it must correspond to an entry in the Works Cited page.
Given the options presented, the best MLA citation among the choices would be "Some groups of people have a greater chance of infection and severe illness." ("Article 3"). In this case, 'Article 3' is presumably a stand-in for the actual title of the web page where the information was found since the actual name was not provided.
Please note that in formal MLA citation, 'Article 3' should be replaced with the actual title or a clear shortened version of the title of the web article referenced. Since each option merely references 'Article 3,' the closest to correct MLA formatting is option D which provides a direct quote and the article title without other unnecessary information.