Topic: Interchange of Parts of Speech,

Best Answer Explained in Below-:

The correct noun form of the adjective "pious" is "c) Piety." Understanding the relationship between the terms involves recognizing that "pious" describes a person or behavior characterized by religious devotion or moral righteousness. The transformation of adjectives into nouns typically adheres to certain linguistic patterns, and in this case, "piety" captures the essence of being pious.

The term "piety" specifically refers to the quality of being pious; it encompasses concepts of reverence, duty to God, and religious observance. In contrast, "piousness" (option A) may appear to be a noun form, but it is less commonly used and isn't as widely accepted in formal language. "Pousity" (option B) is not a recognized English word, making it incorrect. Lastly, "Pity" (option D) is unrelated to the concept of piety as it refers to compassion or sorrow for someone else's misfortune.

Therefore, "Piety" is the most accurate noun form representing the characteristics denoted by "pious," as it encapsulates the qualities of devotion and reverence that the adjective conveys.