Final answer:
The software with code freely available to the public is open source software. Unlike proprietary software, open source software allows anyone to access, modify, and distribute the code. Software developers typically work in the tertiary sector of the economy, which provides services.
Step-by-step explanation:
The software for which the code is freely available to anyone is referred to as open source software. This means that the computer code behind the software can be accessed, modified, and distributed by anyone. Proprietary software, in contrast, has source code that is not shared with the public and generally requires purchasing a license to use. Open source software is a key part of the movement towards free use and distribution of technology, standing in opposition to the commercialization of software seen historically with operating systems provided by companies like IBM, Microsoft, and others. These companies offered proprietary operating systems, which were only available for use on their respective hardware and came with licensing fees.
Moreover, in response to the question of which sector of an economy a software developer would work in, the correct answer is c. Tertiary. The tertiary sector is responsible for providing services, which includes software development, rather than dealing with the extraction or manufacturing of goods.