How does hemoglobin's Hill plot demonstrate positive cooperativity?

• A. The first region has a slope of 3, indicating positive cooperativity.
• B. The middle region has a slope greater than 1, indicating positive cooperativity.
• C. The last region has a slope of 0, indicating positive cooperativity.
• D. All regions have a slope of 1, indicating positive cooperativity.

Answer: (B)