The correct answer is Encryption because it safeguards data by encoding it so that only authorized parties can decrypt and access the information, ensuring both its confidentiality and integrity while in transit. Resource policies set permissions and conditions for resource access but do not protect data in transit. Secrets management is used for securely storing and managing sensitive data like APIs keys and credentials rather than encrypting data in transit. Storage refers to how data is housed in the cloud and doesn’t directly protect it when it’s being transported. Replication involves copying data to ensure availability and redundancy but does not provide encryption or protect the integrity of the data as it travels between services. High availability ensures that services remain available even during outages or attacks but isn't a control that specifically addresses the encryption of data in transit.