The primary benefit of DevOps, within the context of Disciplined Agile, isreduced cost of deployments. DevOps is a set of practices that aims to shorten the systems development life cycle and provide continuous delivery with high software quality. In DA, DevOps practices facilitate seamless integration and continuous delivery of code changes, enabling more frequent and reliable releases to production.

By automating and streamlining deployment processes, DevOps reduces the manual effort, time, and errors associated with deployments, which, in turn, lowers the overall cost. This aligns with the Disciplined Agile principle of "optimize flow across the entire value stream," which emphasizes efficient and cost-effective delivery of value.

Additionally, reducing the cost of deployments leads to other secondary benefits such as improved quality (due to more frequent testing and feedback loops) and greater agility (by enabling quicker response to changing market or customer needs). Therefore, while other options may seem beneficial, the most direct and primary benefit associated with DevOps is indeed the reduced cost of deployments.