Which category of software is protected by copyright laws but is available at no cost?

Closed-source software is proprietary, meaning its source code is not available for public view or modification. While this category can sometimes be offered for free, it is typically associated with licensing fees and restrictions. Closed-source software generally does not fit the description of being freely available at no cost.

Shareware is a type of software that is initially provided for free but often comes with limitations or a trial period. Users are typically required to purchase a license after the trial ends to continue using the software beyond its basic features. Therefore, shareware does not fit the definition of software that is entirely free and protected by copyright.

Public domain software is not protected by copyright, meaning it can be freely used, modified, and distributed without restrictions. Unlike freeware, which retains copyright protection, public domain software does not require permission from any creator, making it fundamentally different in terms of legal ownership.