Consider a graph that represents acquaintances among people. Each vertex represents a person. Each edge represents an acquaintance between two people.
a. Is this graph directed or undirected?
b. Consider all vertices adjacent to a given vertex x. What does this set of vertices represent?
c. What does a path in this graph represent?
d. In what circumstance might one want to know the shortest path between two vertices in this graph?
e. Is the graph associated with all the people alive on January 1, 1995, connected? Justify your answer.