In software licensing and distribution, which type of software is freely available and allows anyone to view, edit, modify, and customize its source code according to their needs, subject to the license terms?

Introduction / Context:
This general knowledge question is about the concept of open source software, which has become a major part of modern computing. Many popular tools, from operating systems like Linux to databases and programming languages, are distributed under open source licenses. Understanding what open source means helps you distinguish between software that is simply free to use and software that can be studied, modified, and shared by the community. This is important for students, developers, and users who want to participate in collaborative technology projects.

Given Data / Assumptions:

• The question asks about software that is freely available and can be edited and customized by anyone.
• The options use phrases such as Free Source, Open Source, Easy Source, and Unpaid Source.
• We assume standard definitions from organizations such as the Open Source Initiative, which describe legal and practical aspects of open source licenses.
• We assume that the key points are access to source code and the right to modify and redistribute that code.

Concept / Approach:
Open source software is defined by licenses that give users the freedom to access the source code, modify it, and redistribute original or modified versions under certain conditions. The word open refers to openness of the code, not simply to price. By contrast, some software is free to use but does not provide source code or permit modification; this is often called freeware or proprietary software with a zero price. Terms like Free Source, Easy Source, and Unpaid Source are not standard categories and do not guarantee that source code is available. Therefore, the correct term for software that is both freely available and open to editing and customization is open source software.

Step-by-Step Solution:
Step 1: Identify the essential features described in the question: free availability and the ability to edit and customize the software.Step 2: Recall that open source licenses allow users to view, change, and share source code.Step 3: Evaluate whether Free Source, Easy Source, or Unpaid Source are recognized terms in software licensing; they are not.Step 4: Recognize that Open Source is the widely accepted term used in documentation, communities, and legal licenses.Step 5: Conclude that open source software is the type described by the question.

Verification / Alternative check:
Examples of open source projects include the Linux kernel, the Apache web server, the MySQL and PostgreSQL databases, and many programming languages such as Python. All of these provide source code openly. Developers can download the code, study how it works, modify it, and contribute changes back to the project subject to license terms. Official definitions from the Open Source Initiative list criteria such as free redistribution, access to source code, and the right to create derived works. These criteria match the description in the question, confirming that open source is the correct answer.

Why Other Options Are Wrong:
Option A is incorrect because Free Source is not a recognized standard term and could be misunderstood as merely free of cost without guaranteeing code access. Option C is incorrect because Easy Source suggests ease of use but says nothing about source code availability or modification rights. Option D is incorrect because Unpaid Source focuses on the price and does not ensure that the code is open to editing. Only option B, open source software whose source code is available for use, modification, and redistribution, aligns with the widely accepted definition of the term.

Common Pitfalls:
A common misunderstanding is to equate open source with free of cost. Some open source software may be sold as part of support services or bundled distributions, yet still be open to modification. Conversely, some freeware is free to download but remains closed source and cannot be legally modified. Another pitfall is ignoring license requirements such as attribution or sharing changes under the same license. Users and developers should read license terms carefully and remember that open source describes freedoms related to code, not just pricing or ease of use.

Final Answer:
The correct answer is Open Source software whose source code is available for use, modification, and redistribution.