The correct answer is A. Document reader.
A document reader is a machine that can read documents that are encoded in a way that is readable by both humans and machines. This includes documents that are printed on paper, as well as documents that are stored electronically. Document readers are often used in businesses and other organizations to scan and digitize documents, which can then be stored electronically or shared with others.
A distributed system is a system that consists of multiple computers that are connected together and work together to perform a task. Distributed systems are often used to provide high availability and scalability.
Artificial intelligence (AI) is a branch of computer science that deals with the creation of intelligent agents, which are systems that can reason, learn, and act autonomously. AI is often used to create systems that can perform tasks that are difficult or impossible for humans to do, such as playing games or driving cars.
A document sorter is a machine that sorts documents into different categories. Document sorters are often used in businesses and other organizations to sort incoming mail or to sort documents for archiving.
Therefore, the correct answer is A. Document reader.