Regional cooperation is most accurately described by which of the following?

a.
When urban communities decide that it is in their mutual best interest to refrain from forming partnerships

b.
When urban communities enhance communication channels in order to better surveil the communities within the region

c.
When urban communities within one particular region adjust their budgets to better compete with each other for economic resources

d.
When urban communities work together to compete with communities in other regions

e.
All of the above