Answer:
make treaties with neighboring states that allow trade through their territory
Step-by-step explanation:
A landlocked country like bolivia is a country that has no sea access. In order to trade successfully Bolivia has to be part of a treaty with a coastal country also called a transit state.
This kind of treaty came about in a united nations convention on transit trade as it concerns landlocked countries.
The countries that serve as transit states are to allow trade on their territory. They are not to discriminate on the place of origin of these goods nor there destination.