A dedicated computer is a computer that is assigned one and only one task. This means that the computer is not used for any other purpose other than the task it is assigned to. For example, a dedicated computer might be used to control a machine in a factory, or to run a scientific experiment.
Option A is incorrect because a dedicated computer can be used by multiple people. For example, a dedicated computer might be used by a group of scientists to run an experiment.
Option B is correct because a dedicated computer is assigned one and only one task.
Option C is incorrect because a dedicated computer can use multiple kinds of software. For example, a dedicated computer might use software to control a machine, and software to collect data.
Option D is incorrect because a dedicated computer is not necessarily meant for application software. For example, a dedicated computer might be used to control a machine in a factory.