The question describes the security service of non-repudiation, which is the ability to prove that a specific action or event has taken place, preventing the originator from denying it. While non-repudiation is not an option, it is fundamentally dependent on the property of integrity. Integrity is the property of maintaining the accuracy and completeness of data. To prove an event occurred (non-repudiation), the evidence for that event (e.g., system logs, transaction records, digital signatures) must be reliable and unaltered. If the integrity of the evidence is compromised, it cannot be used as proof. Therefore, integrity is the foundational property that enables the proof of a claimed event.

A. Electronic chain letters: This is a type of unsolicited message or social engineering tactic, not a fundamental security property of information.

C. Availability: This property ensures that information is accessible and usable upon demand by an authorized entity; it does not relate to proving past events.

D. Accessibility: This is a characteristic related to availability, focusing on the ease of use and access, not a core security principle for proving events.

1. ISO/IEC 27000:2018, Information technology — Security techniques — Information security management systems — Overview and vocabulary.

Section 3.36 defines non-repudiation as the "ability to prove the occurrence of a claimed event or action and its originating entities," which directly matches the question's phrasing.

Section 3.28 defines integrity as the "property of accuracy and completeness." The standard implicitly links these, as the proof required for non-repudiation depends on the integrity of the underlying data.

2. Al-Hassan, A., & Al-Said, N. (2019). A Review of Information Security Goals. International Journal of Computer Science and Network Security, 19(1), 131-136.

Page 133, Section 2.5: This academic review states, "Non-repudiation is a service that is used to provide proof of the integrity and origin of data. Both the sender and receiver of a message can get a proof that the message was actually sent and received." This source explicitly connects the service of non-repudiation with the foundational requirement of integrity.

3. Pfleeger, C. P., Pfleeger, S. L., & Margulies, J. (2015). Security in Computing (5th ed.). Pearson Education.

Chapter 1, Section 1.2.2, "Integrity": The text explains that integrity includes the correctness of data and its origin. It discusses how mechanisms that ensure integrity are also used to provide authenticity and accountability, which are prerequisites for non-repudiation. This establishes integrity as the necessary foundation.