What kind of graph (from Table 1) can be used to model
a highway system between major cities where
a) there is an edge between the vertices representing
cities if there is an interstate highway between them?
b) there is an edge between the vertices representing
cities for each interstate highway between them?
c) there is an edge between the vertices representing
cities for each interstate highway between them, and
there is a loop at the vertex representing a city if there
is an interstate highway that circles this city?