A cloud engineer is setting up controls between VPCs. Which of the following should the engineer use?

The correct choice involves using NAC lists, which stands for Network Access Control lists. NAC lists are essential for managing and controlling the flow of traffic between different Virtual Private Clouds (VPCs) within a cloud environment. They enable the cloud engineer to define rules that determine which types of traffic are allowed or denied between VPCs based on specified criteria such as IP address, protocol, and port number. This level of control is critical for enhancing security by ensuring that only authorized communication can occur between the VPCs, thus limiting exposure to potential threats.

In contrast, other options like VNET refers to a virtual network typically used within Azure environments, but it does not specifically address the control of traffic between VPCs. Screened subnets are typically used in traditional network architectures for security but don't apply directly to the context of controlling inter-VPC traffic. A jump box is a secure intermediary used primarily for administrative access rather than controlling traffic flows. Therefore, NAC lists serve as the most suitable choice for implementing effective access controls between VPCs in a cloud infrastructure.