An argument states: "To improve student performance, the local school district should extend the school day by one hour, as students in a neighboring district with longer school days consistently achieve higher test scores."

The correct answer to the question "An argument states: "To improve student performance, the local school district should extend the school day by one hour, as students in a neighboring district with longer school days consistently achieve higher test scores."" is Option D: Other factors known to influence test scores, such as socioeconomic status, are comparable between the two districts..

The other options — A) The neighboring district's curriculum is identical to the local district's., B) Teachers in both districts have similar levels of experience and qualifications., C) Students in the neighboring district do not participate in more extracurricular activities. — are incorrect for this GMAT Exam Prep question. As explained above: To establish a causal link, it's critical to rule out other potential causes for higher test scores. If socioeconomic status and other influencing factors are similar, the argument for the extended d…