When a citation includes three to five authors, you should:

include only the first author's last name in each citation $($the other authors are listed in the reference section$).$

always include the first two authors' last names in each citation $($the other authors are listed in the reference section$).$

include each author's last name in the first citation; subsequent citations include the first author's last name followed by et al$.$

always include each author's last name in the citation.