Why is hemoglobin considered a more efficient oxygen transporter than myoglobin?

Myoglobin exhibits positive cooperativity and releases oxygen more effectively at lower partial pressures.

Hemoglobin has a higher oxygen affinity than myoglobin, making it a better transporter.

Myoglobin has a lower oxygen affinity than hemoglobin, making it a better transporter.

Hemoglobin exhibits positive cooperativity and releases oxygen more effectively at lower partial pressures.