The correct option is C gelatin
Gelatin is a mixture of peptides and proteins produced by hydrolysis of collagen extracted from the connective tissues of animals. Therefore, collagen when boiled in water it turns into gelatin.
Amino acids are monomers of the protein.
All the connective tissue cells secretes fibres of structural proteins called collagen and elastin. The fibres provide strength, elasticity and flexibility to the tissues.
Bone cells are called osteocytes