Correct option is (d) Calcium Hydroxyapatite
For explanation I would say: Calcium Hydroxyapatite is a biomaterial which had properties closest to that of the human bone. It is found in shells of animals and can also be manufactured in labs. Whenever an implant regarding bones is manufactured, they are coated with calcium hydroxyapatite to allow better integration of the implant with the bone and reduce immuno-rejection.