Final answer:
The Grantor must sign a deed to make it valid. Witnesses and a Notary Public might also be required depending on jurisdiction to attest to the authenticity of the signature and make the deed legally binding. So, the correct answer is option d.
Step-by-step explanation:
The party that must sign a deed to make it valid is the Grantor. The grantor is the person or entity transferring the property to another party, known as the grantee. While the grantor's signature is essential, the grantee is not required to sign the deed for the transfer to be effective.
However, the deed signing usually needs to be witnessed and often notarized to ensure that it is legally binding and that the signature is authentic. Depending on the state, one or more witnesses may be required, and the document may also need to be notarized by a Notary Public.