Final answer:
Understanding abstract concepts like a square involves the application of various cognitive tools.
Step-by-step explanation:
According to the provided information, understanding abstract concepts like a square involves the application of various cognitive tools. This means that it goes beyond relying solely on mental pictures or visual perception of absolute distances. The mind's capacity to solve diverse problems, using different cognitive strategies like forming mental images, verbal reasoning, logical thinking, and numerical analysis, contributes to a deeper understanding of abstract concepts. Therefore, the correct answer is c) Application of various cognitive tools.