An organization's security officer is actively developing a new data protection strategy. The plan aims to fortify the integrity of data stored on the company's servers to uphold the confidentiality, integrity, and availability $($CIA$)$ triad principles. In this development process, which data protection method should the security officer primarily implement to ensure the accuracy and consistency of data over its entire life cycle, according to the principles of the CIA triad, particularly focusing on enhancing the "integrity" aspect?

a$.$

Checksum verification

b$.$

Data encryption

c$.$

Data backup

d$.$

User access controls