The following statement about directed graph is correct? ()
A.Any vertex in a strongly connected graph has an arc to all other vertices
B.A directed complete graph must be strongly connected
C.The in degree of a vertex in a directed complete graph is equal to the out degree
D.Subsets of edge sets and vertex sets of a directed graph can form subgraphs of the original graph
Answer:B
The following statement about directed graph is correct? ()
A.Any vertex in a strongly connected graph has an arc to all other vertices B.A directed complete graph must be strongly connected C.The in degree of a vertex in a directed complete graph is equal to the out degree D.Subsets of edge sets and vertex sets of a directed graph can form subgraphs of the original graph