What openssl command will generate a selfsigned test certificate?

A.
openssl req new x509 key privkey.pem out cacert.pem days 365

B.
openssl sign key privkey.pem out cacert.pem days 365

C.
openssl req key privkey.pem out cacert.pem days 365

D.
openssl sign new x509 key privkey.pem out cacert.pem days 365