In XML processing, how are XML documents commonly accessed and manipulated programmatically by applications?

Introduction / Context:
Extensible Markup Language, or XML, is widely used for configuration files, data exchange, and web services. Applications rarely treat XML as plain text; instead, they use standard APIs to parse and manipulate XML structures. This question asks how XML documents are commonly accessed programmatically, which is essential knowledge for working with XML in many programming languages.

Given Data / Assumptions:

• XML documents are structured as elements, attributes, and text nodes.
• Applications need to read and sometimes modify XML content.
• Standard APIs exist for parsing and manipulating XML.
• We aim to identify the most common model used to represent XML in memory.

Concept / Approach:
One of the most widely used models for XML is the Document Object Model, or DOM. The DOM represents the XML document as a tree of node objects, where each element, attribute, and text segment is a node. Program code can traverse this tree, query nodes, change values, and add or remove elements. While other methods such as streaming parsers exist, the question asks in a general way how documents are accessed and manipulated, making DOM the best match.

Step-by-Step Solution:
1. Recall that XML is hierarchical and naturally represented as a tree.2. DOM APIs in languages like Java, JavaScript, and C sharp load the entire XML file into memory as a tree.3. Option A states that documents are loaded into a Document Object Model tree so that nodes can be traversed and modified by code. This matches standard practice.4. Option B claims XML can only be edited manually, which is clearly false because many applications parse XML automatically.5. Option C suggests converting XML into image files, which is not a normal way to process XML data.6. Option D says XML can only be accessed by relational databases using SQL, which is incorrect; XML libraries exist for many environments and do not require a database.7. Therefore, Option A is the correct answer.

Verification / Alternative check:
If you look at code examples in Java or JavaScript, you will often see XML parsed using DOM parsers. For example, Java uses javax.xml.parsers.DocumentBuilder to create a Document object, which represents the DOM. Similarly, browsers represent HTML and XML documents as DOM trees that scripts can manipulate. This confirms that loading documents into a DOM tree and traversing nodes is a common way to access and manipulate XML.

Why Other Options Are Wrong:
Option B is wrong because manual editing is only one possibility; it does not explain how applications handle XML.Option C is wrong because image conversion does not preserve XML structure for computation.Option D is wrong because relational databases and SQL are not required for typical XML handling and may not even be involved.

Common Pitfalls:
Developers sometimes choose DOM parsing for very large XML files without considering memory usage, since DOM loads the entire document. In such cases, streaming parsers such as SAX or StAX can be better. However, for many configuration files and moderate sized documents, DOM is convenient and widely supported, making it the default approach in many tutorials and frameworks.

Final Answer:
They are loaded into a Document Object Model tree so that nodes can be traversed and modified by code.