What Format of Machine Name Does an Interactive Client or Application

What format of machine name does an Interactive Client or Application Server use to establish a direct connection with a Runtime Resource?

A) It always uses the short machine name (e.g. robot001)
B) It always uses the fully qualified domain name (FQDN) (e.g. robot001.mydomain.local)
C) It depends on the system wide setting which indicates whether short name or FQDN will be used
D) It uses the format of the name specified on the certificate that is associated with the Runtime Resource