Which statement about the OPSF debug output is true?
A. The output displays OSPF hello messages which router R1 has sent or received on interface Fa0/1.
B. The output displays OSPF messages which router R1 has sent or received on all interfaces.
C. The output displays OSPF messages which router R1 has sent or received on interface Fa0/1.
D. The output displays OSPF hello and LSACK messages which router R1 has sent or received.
debug ip ospf hello : only display hello message
debug condition interface fa0/1: further only display the hello message that sent or received from or to the interface f0/1
debug ip ospf hello : only display hello message
debug condition interface fa0/1: further only display the hello message that sent or received from or to the interface f0/1