The correct answer is: a) Kushana Empire.
The Kushan Empire was a major power in Central Asia and the Indian subcontinent from the 1st to the 3rd centuries CE. It was founded by Kushan, a Kushan prince who conquered the region around Bactria in the early 1st century CE. The Kushan Empire reached its peak under the reign of Kanishka the Great (c. 127-150 CE), who extended its rule over much of Central Asia, the Indian subcontinent, and parts of China.
The Kushan Empire was a major center of trade and culture. It was a cosmopolitan empire, with people from different cultures and religions living together. The Kushans were patrons of Buddhism, and they built many Buddhist temples and stupas. They also minted coins with Buddhist images.
Archaeological finds in Sikkim, like stupas and coins, suggest influences from the Kushan Empire. For example, the Char Dham Stupa in Sikkim is a Buddhist stupa that is thought to have been built by the Kushans. The stupa is decorated with images of the Buddha and other Buddhist figures.
The Kushan Empire was a major power in Central Asia and the Indian subcontinent for over two centuries. It was a cosmopolitan empire that was a center of trade and culture. The Kushans were patrons of Buddhism, and they built many Buddhist temples and stupas. Archaeological finds in Sikkim, like stupas and coins, suggest influences from the Kushan Empire.