which group of countries became the first to create a “Travel Bubble” allowing their citizens to travel freely between their borders during the cronavirus pandemic?

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which group of countries became the first to create a “Travel Bubble” allowing their citizens to travel freely between their borders during the cronavirus pandemic?

A. Scandavian States
B. Caucasian States
C. Baltic States 
D. Benelux Union

Latvia, Lithuania and Estonia will open their borders to each others’ citizens from May 15, creating a Baltic “travel bubble” within the European Union amid an easing of pandemic restrictions