Bangladesh's official currency is the Bangladeshi taka (currency code: BDT). While it's often casually referred to as just 'taka', the formal and complete name is 'Bangladeshi taka' to distinguish it from historical taka currencies in the region. The Euro is used by European Union countries. The rupee is used by India, Pakistan, Sri Lanka, and other South Asian nations, but not Bangladesh. Option B ('taka' alone) is informally correct but option C gives the complete official name.