This question tests the basic understanding of an operating system's main purpose. The correct answer is B, as the primary role of an operating system is to manage hardware and software resources, ensuring that different programs and users running on the computer do not interfere with each other. Option A is a function of the operating system but not its main purpose. Option C is a function of antivirus software, not the operating system itself. Option D is unrelated to the operating system's main purpose.