Bone resorption markers are -: (A) Serum propeptide of type I procollagen, (B) Osteocalcin, (C) Urine total free deoxypyridinoline, (D) Free glutamic acid cross linkage
Answer is C. Markers of bone resorption

Urine & serum cross-linked N telopeptide
Urine & serum cross-linked C telopeptide
Urine total free deoxypyridinoline
Urine hydroxyproline
Urine hydroxylysine glycosides
Serum tartrate-resistant acid phosphatase
Serum bone sialoprotein