Which two steps are required to use certificates with a certificate authority?

Your company has VPNs that connect to other companies. The company wants to use certificates with a recognized third-patty certificate authority.

Which two steps are required to use certificates with a certificate authority? (Choose two)

A.
Configure a CRL

B.
Configure RSA signatures for the IKE authentication method

C.
Configure DSA signatures for the IKE authentication method

D.
Generate a certificate request for the SRX device