Marker for bone formation is:

Ans. is 'b' ie Osteocalcin "Osteoblasts are bone forming cells that synthesize the collagenous component of the osteoid matrix. They also initial the process of bone mineralization though the elaboration of osteocalcin and calcium binding proteins (osteonectin and bone sialo protein) required for the deposition of inorganic hydroxyapatite in the organic osteoid that they produce. Osteocalcin is a product of osteoblast uniquely and is measurable in the serum. Thus it is a sensitive and specific marker of osteoblastic activity."