An administrator is creating a secure method for a contractor to access a test environment. Which of the following would provide the contractor with the best access to the test environment?

A jump server (or jump host) provides a hardened, intermediary host that contractors can connect to first, and then from there, access the target test environment. This creates a secure, audited, and controlled pathway, isolating the internal network from direct external access. An application server hosts applications but doesn't inherently provide secure access control for external users to an internal network. An RDP server facilitates remote desktop connections but doesn't offer the same level of security segmentation and control as a jump server for external access to a sensitive environment. A proxy server acts as an intermediary for requests from clients seeking resources from other servers, primarily for filtering or caching, not for secure, controlled access to an internal test environment by external users.