Type 1 hypervisors operate directly on the underlying hardware, making them more efficient and suitable for server-level virtualization. In contrast, Type 2 hypervisors run on a host operating system, adding a layer of abstraction that can impact performance.

Virtual memory serves as a logical extension of physical memory, allowing the operating system to use secondary storage as an extension of RAM. This aids in managing larger programs and multitasking efficiently.

In this scenario, setting up a staging environment that closely resembles the production environment is crucial for effective debugging. It helps in replicating the issue consistently and enables thorough testing to identify the root cause of the intermittent failure.

NAT (Network Address Translation) allows multiple devices within a local network to share a single Private IP address. This Private IP address is usually assigned within the local network and is not routable on the public internet. Hence, "Private" is the correct option.

NgRx Store in Angular helps maintain consistent state across components by providing a centralized state management solution. It uses reactive programming concepts and facilitates easier state management in complex applications.

The Agile principle of "delivering working software frequently" emphasizes the importance of delivering usable software increments regularly. Continuous Integration is a practice that aligns well with this principle, as it involves frequently integrating code changes from multiple developers into a shared repository. This integration is followed by automated tests to ensure that the software remains functional and bug-free. Sprint Review is a ceremony in Agile where the team showcases the completed work to stakeholders, but it doesn't directly relate to the continuous delivery of working software. Test-Driven Development (TDD) is a development approach where tests are written before the code, aiding in software quality but not directly addressing frequent delivery. The Waterfall Model, in contrast, is a traditional sequential development approach that doesn't prioritize frequent software delivery. Therefore, Continuous Integration is the practice that best supports the Agile principle of delivering working software frequently.

Option 3, concat(), is used to concatenate two strings. In many programming languages such as Java and JavaScript, this operation is represented by the '+' operator or specific functions/methods like concat(). It joins the contents of two strings into a single string.

The correct option is "TCP." TCP (Transmission Control Protocol) is a connection-oriented protocol in the TCP/IP suite. It provides reliable and ordered delivery of data between two hosts by establishing a connection, acknowledging data receipt, and handling retransmissions if packets are lost. UDP (Option 1), on the other hand, is a connectionless protocol that is faster but less reliable. HTTP (Option 2) is a protocol used for web communication, operating at the Application layer. IP (Option 4) is a network layer protocol responsible for addressing and routing.

The Proxy design pattern acts as a surrogate or placeholder for another object and controls access to it. On the other hand, the Decorator pattern dynamically adds new functionality to an object without altering its structure. Proxy focuses on controlling access, while Decorator focuses on adding responsibilities. Understanding these distinctions is crucial when deciding which pattern to use in a given context.

Merge sort has the best time complexity in the worst-case scenario among the given options. It has a time complexity of O(n log n) in all cases, making it efficient for large datasets. Quick sort can have a worst-case time complexity of O(n^2) in certain scenarios, making it less preferable for worst-case scenarios compared to merge sort.