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.