What are ingredients of a valid adoption by Hindu?

The Hindu Adoptions and Maintenance Act, 1956 deals with adoption by any Hindu. The Act prescribes following requisites for a valid adoption:

a. The person who is adopting must have capacity and right to take adoption.

        b. Similarly, the person who is giving in adoption must have capacity to give in adoption.

c. The person who is being adopted must be capable of being adopted.

        d. The process of adoption shall be in conformity with the provisions of the Hindu Adoption and Maintenance Act, 1956.

e. No payments shall be received or given in consideration of adoption.