By definition, a state must have a body of people with a defined territory and

hello,

the steamboat is your answer.

it seems like its the only form of transportation on the choices.

answer is b.

  it is always the best policy to have good communication and good relations between individuals and, specially, between leaders of the countries. for this purpose, among others, there is a common place, the united nations, where the representants can present his and learn about the other country's policies.