Upon receipt of the initial signed digital certificate the user will decrypt the certificate with the public key of the:

A.
registration authority (RA).

B.
certificate authority (CA).

C.
certificate repository.

D.
receiver.

Explanation:
A certificate authority (CA) is a network authority that issues and manages security credentials and public keys
for message encryption. As a part of the public key infrastructure, a CA checks with a registration authority (RA)
to verify information provided by the requestor of a digital certificate. If the RA verifies the requestor’s
information, the CA can issue a certificate. The CA signs the certificate with its private key for distribution to the
user. Upon receipt, the user will decrypt the certificate with the CA’s public key.