What will Karel do when given an unsupported command?

Karel's behavior when given an unsupported command is best described by the option that states Karel will throw an error. In programming environments, particularly those that follow stricter language rules, any command that Karel attempts to execute must be valid within its language specification. If a command does not conform to the predefined set of commands or the rules set for Karel, the interpreter or compiler recognizes this as an invalid command. Consequently, it generates an error to signal that something is wrong, typically providing feedback on the specific nature of the mistake.

This error handling serves an essential purpose in debugging and helps users understand that they need to correct or revise their code before Karel can execute it successfully. Other behaviors, such as ignoring the command or stopping altogether, would not provide the guidance that throwing an error does.