. Which of these inform us on how users will react to a system*1 pointComputerHardwarePropositional representation

None of the options provided (Computer, Hardware, Propositional representation) directly inform us on how users will react to a system. User reactions are typically gauged through user testing, surveys, and feedback mechanisms. These methods provide direct information about user experiences and reactions.

However, if we were to choose the most relevant from the given options, "Propositional representation" could potentially give some insights. Propositional representation is a form of knowledge representation in artificial intelligence, which could indirectly give some insights into user behavior based on how the AI system interacts and learns from the user. But it's important to note that this is indirect and not a direct measure of user reactions.