Question 68 :What is a Java servlet?This type of question contains radio buttons and checkboxes for selection of options. Use Tab for navigation and Enter or space to select the option.optionAA graphic format that resides on a server, extending the server's functionalityoptionBA dedicated Java program that runs in place of the server's operating systemoptionCA graphic format that is compatible with Sun Java System Web Server 6.1optionDA dedicated Java program that resides on a server, extending the server's functionality

A Java servlet is option D: A dedicated Java program that resides on a server, extending the server's functionality.

Here's a step-by-step explanation:

1. A Java servlet is a Java software component that extends the capabilities of a server.

2. Unlike a "standalone" Java application, a servlet cannot run on its own. Instead, it must be run within a "servlet container" which provides the necessary runtime environment.

3. The servlet container is a part of a web server or application server that provides the network services over which requests and responses are sent, decodes MIME-based requests and formats MIME-based responses.

4. A servlet can handle multiple requests concurrently, and can synchronize requests. This allows servlets to support systems such as online trading and interactive games where multiple, simultaneous client requests might need to access and manipulate shared data.

5. Servlets are designed to respond to HTTP requests from clients, typically web browsers, and return HTTP responses. However, they can also be used with other types of request-response protocols.