Synthesize the concept of the threshold effect in hemoglobin and its significance in oxygen release to tissues.

• A. The threshold effect has no impact on hemoglobin's oxygen release to tissues.
• B. The threshold effect prevents hemoglobin from releasing oxygen to tissues, reducing oxygen delivery.
• C. The threshold effect allows hemoglobin to release more oxygen to tissues with lower oxygen levels, optimizing oxygen delivery.
• D. The threshold effect causes hemoglobin to release oxygen only at high oxygen levels, limiting oxygen delivery.

Answer: (C)