Step 1: Analyzing statement (I).
Khadar (New) and Bangar (Old) are types of alluvial soil. Khadar is the younger, fertile soil found near riverbeds, and Bangar is older, less fertile soil found away from riverbeds.
Thus, statement (I) is correct.
Step 2: Analyzing statement (II).
Regur soil, also known as black soil, is ideal for cotton cultivation due to its moisture retention capacity and high fertility.
Thus, statement (II) is correct.
Step 3: Conclusion.
Both statements (I) and (II) are correct. Hence, the answer is (C).