Final answer:
The sudden realization of a solution to an ill-structured problem is evidence for Insight, which is a form of problem-solving involving past experiences and reasoning. It differs from heuristics, which are mental shortcuts, and algorithms, which are systematic methods for solving problems.
Step-by-step explanation:
When individuals are actively trying to solve an ill-structured problem, they often experience a sudden realization of the solution, which is referred to as an insight. This phenomenon occurs without the solver being aware that they are close to a solution, suggesting a sudden internal cognitive reorganization. This is used as evidence for Insight (option 4), which is a form of problem-solving that can happen when relying on past experiences and reasoning, and is considered a facet of creativity and intelligence. On the other hand, a heuristic is a mental shortcut used for problem solving, often in the form of a general rule of thumb. While an algorithm is a systematic, step-by-step problem-solving strategy that guarantees a correct result, and incubation refers to a period of time taken away from a problem that sometimes leads to a solution upon returning to the problem.