The sentence compares two concepts, and the correct answer should reflect the idea that one concept is more common or prevalent than the other. "Imitation" refers to the act of copying or reproducing something, which is more frequent and less original compared to "innovation," which involves creating something new and unique.
Option (B), impracticality ... knowledge, is incorrect because "impracticality" and "knowledge" are unrelated in this context. The comparison should be between two processes or concepts, not an abstract and practical idea.
Option (C), improvisation ... improvement, is not ideal because improvisation is about spontaneous actions, while improvement refers to purposeful action. The comparison between the two doesn’t work as well as imitation versus innovation.
Option (D), improbability ... probability, doesn’t fit the context because "improbability" and "probability" refer to statistical concepts, not the creative processes that "imitation" and "innovation" address.
Thus, option (A) is the correct answer.