According to MLA style, the part of the citation that would be referenced as the source in an in-text citation is:
1. Wysocki
The abbreviation et al. means that there are multiple authors, however for the in-text citation in MLA style, one only needs to mention the last name of the author that appears in the works cited. In this case, Wysocki is the first item that appears in the works cited. As a general rule, the in-text citation should be the first item that appears in the works cited. For instance, if an article has no author then the in-text citation would include the article's title.
The in-text citation should be
(Wysocki 2004) or
According to Wysocki.... (2004)
The year helps the reader identify which book or work one is referring to, but the source is the author.