Which of the following records can be exempt from OPRA by executive order?

The correct answer highlights that complaints and investigations alleging discrimination can be exempt from the Open Public Records Act (OPRA) by executive order. This is grounded in the principle of ensuring privacy and confidentiality, particularly when sensitive information is involved. Complaints regarding discrimination can often contain personal and sensitive details that, if disclosed, may lead to retaliation or harm to individuals involved.

In contexts where government transparency and accountability are vital, certain types of records can still be restricted to protect the rights and privacy of individuals. The ability to exempt these records by executive order reflects a balance between the public's right to access information and the need to safeguard sensitive information that, if released, could undermine the effectiveness of investigations or the safety of individuals.

The other choices do not carry the same level of sensitivity or potential harm that would warrant exemption from OPRA. Records that enhance government transparency or public testimony in government hearings aim to promote openness and accountability. Meanwhile, advertising materials prepared by the government are typically intended for public dissemination, and thus, they do not fall under the same protective measures.