What method allows Karel to remember where it has been?

Karel the robot does not have the capability to inherently remember its previous locations or paths without additional programming. To keep track of where Karel has been, programmers need to implement a tracking system manually, which often involves using variables or placing markers in the environment. This allows Karel to remember its movements and avoid retracing steps unnecessarily.

This answers the question accurately, as it reflects the necessity for explicit programming to enable Karel to track its location during execution. The other options imply automatic memory retention or specific methods that Karel does not possess within its basic operational framework. Hence, the emphasis on manual tracking is essential for understanding Karel's limitations regarding spatial awareness in programming scenarios.