Integrity is best defined as:

Integrity refers to the assurance that information is accurate, consistent, and reliable over its lifecycle. In the context of data security, it primarily focuses on the accuracy and authenticity of data, ensuring that it remains unaltered from its original state during storage or transmission.

The correct definition emphasizes that integrity involves data being delivered from the source to the intended receiver without being altered. This means that any modifications or corruptions during the transfer process could potentially compromise the integrity of the data, making it crucial for information systems to ensure that no unauthorized changes occur.

While maintaining correct and current data is important, the broader definition of integrity primarily highlights the importance of protecting the original state of the data as it travels from point A to point B, without unauthorized alterations. Other aspects, such as data protection from unauthorized access or ensuring availability when required, focus on different principles like confidentiality and availability, respectively.