What does Artificial Intelligence (AI) primarily refer to?

Artificial Intelligence (AI) primarily refers to the simulation of human intelligence processes by machines. This involves creating systems that can perform tasks typically requiring human intelligence, such as learning, reasoning, problem-solving, perception, language understanding, and decision-making. The essence of AI is to enable machines to mimic cognitive functions that are associated with the human mind, allowing them to operate in ways that seem intelligent.

The focus is on replicating aspects of human thought and behavior, which is a cornerstone of what distinguishes AI from mere computational systems. This definition encompasses various subfields within AI, including but not limited to machine learning, natural language processing, and robotics.

The other options, while they touch on different forms of intelligence or simulation, do not accurately encapsulate the broad and specific focus of AI on human-like intelligence processes. For example, simulating animal intelligence processes would be a narrower field, and simulating natural phenomena might relate more to areas like simulation modeling rather than AI itself. The notion of replacing human workers is more about the implications and ethical considerations of AI usage rather than its definition or primary focus.