In basic web development, HTML documents are usually saved in which type of file format on disk?

Introduction / Context:
HTML is the standard markup language for creating web pages. One of the simplest but most important facts about HTML documents is how they are stored on disk. Unlike executable files or proprietary binary formats, HTML files are saved as plain text. Interviewers and basic computer awareness exams often ask this question to ensure that learners understand that they can view and edit HTML source with any text editor, which is central to the open nature of the web.

Given Data / Assumptions:

• An HTML document consists of text based tags such as html, head, body, p, and so on.
• The file is typically saved with extensions like .html or .htm.
• Browsers read the text, parse the tags, and render the page visually.
• The question is not about how browsers internally represent the page after parsing.

Concept / Approach:
HTML documents are purely text based. Historically they used ASCII encoding, and in modern practice they often use Unicode encodings such as UTF-8. Because they are text, any simple editor such as Notepad, VS Code, or Vim can open and edit them. The browser reads the plain text file, interprets the markup, and then constructs a Document Object Model for rendering. The correct answer must therefore identify plain text, not machine language or proprietary binary formats, as the storage format.

Step-by-Step Solution:
Step 1: Consider how you create a basic HTML file manually. You open a text editor, type the HTML tags as text, and save the file with a .html extension. Step 2: When you open this file in a browser, the browser reads the characters and recognises the tags. Step 3: There is no compilation to machine code or special encoding required; the file remains human readable text. Step 4: Option b states that HTML documents are plain ASCII or Unicode text, which matches this behaviour. Step 5: Option a talks about machine language codes, which describe executable binaries, not HTML text pages. Step 6: Option c suggests a special binary format that only browsers can open, which is not true for HTML, because many tools and editors can read and modify these files.

Verification / Alternative check:
You can verify this quickly on any computer. Take an existing web page file, open it with a text editor instead of a browser, and you will see the HTML markup as readable text. You can edit some content, save the file, and reload it in a browser to see the changes. This experiment demonstrates that HTML documents are plain text. In contrast, if you open an executable program file in a text editor, you will see unreadable characters because it is stored in machine code or some other binary format.

Why Other Options Are Wrong:
Option a is wrong because HTML is not executed directly by the CPU. The CPU executes compiled or interpreted code, not markup. Option c is incorrect because HTML is an open standard and can be edited by many tools; it is not a proprietary binary format restricted to browsers. Option d is incorrect because option b already correctly identifies the text based nature of HTML documents.

Common Pitfalls:
Learners sometimes confuse HTML with technologies like Flash or older binary formats that required plugins. They may also think that because modern web pages can be complex and dynamic, the HTML must be compiled, which is not the case. Another pitfall is to forget about character encoding; while HTML is plain text, the encoding must match what is declared in the meta charset tag or HTTP headers to display characters correctly. Remembering that HTML documents are plain text files helps demystify web development and simplifies debugging and editing tasks.

Final Answer:
Plain ASCII or Unicode text that can be edited with a simple text editor.