Which of the following is a qualification for a member of the House of Representatives?

To serve as a member of the House of Representatives, one must be at least 25 years old. This age requirement is established in Article I, Section 2 of the U.S. Constitution, which outlines the fundamental qualifications for this legislative body. The intention behind setting this age limit is to ensure that members have a certain level of maturity and life experience before representing the interests of their constituents in Congress.

The other options present requirements that do not apply to the House of Representatives. For instance, the requirement to be at least 30 years old pertains to the Senate, while citizenship for at least 9 years is also a Senate requirement. The residency requirement mentioned in another option is relevant to federal service, but it is not a specific qualification for the House of Representatives. Therefore, the correct qualification for a representative's eligibility is being at least 25 years of age.