iSCSI is a protocol that allows for the transmission and use of SCSI commands and features over a TCP- based network. iSCSI allows systems to use block-level storage that looks and behaves as a SAN would with physical servers, but to leverage the TCP network within a virtualized environment and cloud.

The relying party is attached to the application or service that a user is trying to access, and it accepts authentication tokens from the user's own identity provider in order to facilitate authentication and access.
The other terms provided are all associated with federated systems, but none is the correct choice in this case.

Explanation
Anonymization is a type of masking, where indirect identifiers are removed from a data set to prevent the mapping back of data to an individual. Although masking refers to the overall approach of covering sensitive data, anonymization is the best answer here because it is more specific to exactly what is being asked.
Tokenization involves the replacement of sensitive data with a key value that can be matched back to the real value. However, it is not focused on indirect identifiers or preventing the matching to an individual.
Encryption refers to the overall process of protecting data via key pairs and protecting confidentiality.

Explanation
It is imperative that applications do checks when each function or portion of the application is accessed to ensure that the user is properly authorized. Without continual checks each time a function is accessed, an attacker could forge requests to access portions of the application where authorization has not been granted.
An injection attack is where a malicious actor sends commands or other arbitrary data through input and data fields with the intent of having the application or system execute the code as part of its normal processing and queries. Cross-site scripting occurs when an attacker is able to send untrusted data to a user's browser without going through validation processes. Cross-site request forgery occurs when an attack forces an authenticated user to send forged requests to an application running under their own access and credentials.