Top Level of a Certificate Authority

A.

In a Public Key Infrastructure (PKI), a Certificate Authority (CA) is responsible for issuing and managing digital certificates. Digital certificates are electronic documents that are used to verify the identity of an entity, such as a website or user, and to secure communication over a network.

The top level of a certificate authority in a PKI is called the Root CA. The Root CA is the highest level of authority in the PKI hierarchy, and it is responsible for issuing and managing digital certificates for other CAs in the hierarchy. The Root CA is trusted by default by all clients and servers in the PKI.

The Root CA generates a self-signed digital certificate, which serves as the basis of trust for the entire PKI. This certificate is installed on all clients and servers in the PKI, and it is used to verify the authenticity of all other digital certificates that are issued by the subordinate CAs in the hierarchy.

Intermediate CAs and Subordinate CAs are lower levels of authority in the PKI hierarchy. An Intermediate CA is a CA that is subordinate to the Root CA and is responsible for issuing digital certificates to other subordinate CAs or end-users. A Subordinate CA is a CA that is subordinate to an Intermediate CA and is responsible for issuing digital certificates to end-users.

Delegated CA is not a term commonly used in the context of PKI, and it is not a correct answer to this question.

In summary, the correct answer to this question is A. Root CA. The Root CA is the top level of a certificate authority in a PKI, and it is responsible for issuing and managing digital certificates for other CAs in the hierarchy.