Which of the following is a primary benefit of using ReST over SOAP?

Using ReST over SOAP primarily benefits from less bandwidth consumption. This is largely due to the lightweight nature of ReST APIs compared to SOAP APIs. ReST typically uses standard HTTP protocols and tends to work with simple formats such as JSON or XML without the added overhead found in SOAP, which often requires extensive XML formatting and additional envelopes for requests and responses. This simplification in data interchange makes ReST more efficient by utilizing fewer bytes for each call, leading to reduced bandwidth usage, especially when the data being transferred is small or less complex.

Furthermore, the other options provided are features that do not uniquely favor ReST over SOAP. Security protocols can be robust in both styles of web services, built-in error handling tends to be more intricate and structured in SOAP, and the stateful nature of operations is typically associated more with SOAP services as they often maintain session state across several requests. This context underscores the advantage of ReST concerning bandwidth efficiency.