To answer this question, the user needs to have a basic understanding of WebSphere cell configuration and its components.
The correct answer is:
A. Deployment Manager
Explanation:
In a WebSphere cell configuration, the Deployment Manager is a single point of failure. The Deployment Manager is responsible for managing the deployment of applications across the cell, and if it fails, it can result in the entire cell being unavailable. The other components, such as the web container, EJB container, and HTTP server, can be distributed across multiple nodes in the cell, providing redundancy and fault tolerance.
Option B, web container, is incorrect because it is responsible for handling HTTP requests and is not a single point of failure.
Option C, EJB container, is incorrect because it manages the execution of EJB components and is not a single point of failure.
Option D, HTTP server, is incorrect because it is responsible for handling HTTP requests and can be distributed across multiple nodes in the cell.
Therefore, the correct answer is A. Deployment Manager.