Bangladesh: noun: Bangladeshi(s)

adjective: Bangladeshi

Barbados: noun: Barbadian(s) or Bajan (colloquial)

adjective: Barbadian or Bajan (colloquial)

Belarus: noun: Belarusian(s)

adjective: Belarusian

Belgium: noun: Belgian(s)

adjective: Belgian

Belize: noun: Belizean(s)

adjective: Belizean