Which is a correctly defined static CRL distribution point?

Which is a correctly defined static CRL distribution point?

A.
HTTP://10.0.1.51/CertEnroll/Austin.crl

B.
FTP://10.0.1.51/CertEnroll/Austin.crl

C.
HTTPS://10.0.1.51/CertEnroll/Austin.crl

D.
TFTP://10.0.1.51/CertEnroll/Austin.crl