Which of these European countries is landlocked?

To which country does Stewart Island belong? To which country does Socotra belong? Which of these South American countries is landlocked? Besides Bolivia, which is the other landlocked country in South America? Which Central European country lost its coastline after World War I and is now landlocked? Which of these Central Asian countries is doubly landlocked? Which European microstate is doubly landlocked? Which Himalayan country is landlocked between China and India?