Concept:
Every country has its own official currency, and questions like this test basic awareness of world currencies, especially of India's neighbours.
Explanation:
The Ngultrum is the official currency of Bhutan, introduced in 1974 and pegged at par with the Indian Rupee, which also circulates freely within the country. Laos uses the Kip as its currency, Bangladesh uses the Taka, and Nepal uses the Nepalese Rupee. None of these three match the Ngultrum.
Final Answer:
Bhutan is the country whose currency is the Ngultrum, so option A is correct.