In a public key infrastructure (PKI), the authority responsible for the identification and authentication
of an applicant for a digital certificate (i.e., certificate subjects) is the:

A.
registration authority (RA).

B.
issuing certification authority (CA).

C.
subject CA.

D.
policy management authority.

Explanation:
A RA is an entity that is responsible for identification and authentication of certificate subjects, but
the RA does not sign or issue certificates. The certificate subject usually interacts with the RA for
completing the process of subscribing to the services of the certification authority in terms of getting
identity validated with standard identification documents, as detailed in the certificate policies of the

CA. In the context of a particular certificate, the issuing CA is the CA that issued the certificate. In
the context of a particular CA certificate, the subject CA is the CA whose public key is certified in
the certificate.