What is the difference between the Main Line Service and the Round the World Service (RTW) routes?

Question 12 options:

1) RTW is a Main Line that extends around the world using Panamax vessels typically

2) RTW is a bi-directional Main Line that extends around the world using Post-Panamax vessels typically

3) Main Line Service uses container vessels while RTW uses Break Bulk vessels

4) Round the World Service routes use Post-Panamax vessels