Can you check my answers please?

One reason why a country might NOT want to join the European Union is

A fear of losing some of its ability to make it's own decisions.***
B the ability to trade easier.
C the protection they will get from the other EU countries.

Your answer is correct. One reason why a country might not want to join the European Union is a fear of losing some of its ability to make its own decisions.

A) Fear of losing some of its ability to make its own decisions is correct. Some countries may be hesitant to join the European Union because they fear that they will have to surrender a certain level of sovereignty and decision-making power to the collective decisions made by the EU.