Answer: a.myoglobin
Step-by-step explanation:
Myoglobin (Mb) and Hemoglobin (Hb) are heme proteins and are part of the family of globular proteins. These proteins are characterized by having the spherical or globular wrapped polypeptide chain having various types of secondary structures. Myoglobin is an extremely compact protein found in muscular cells of vertebrate animals, having as their main function the storage and it also facilitates the transport of oxygen in the muscles. This protein is found in the cardiac muscle and skeletal muscle of the mammals and increases the effective solubility of oxygen in the muscle by acting as an oxygen reservoir and facilitating the diffusion of O2 from the capillaries blood to the mitochondria.