Portuguese explorer Vasco de gamma, so the correct answer is option 'a'.

The Portuguese were the first Europeans to come to India in the late 15th century. Here are some details about their arrival:

Background:
- Portugal was a small country on the western edge of Europe that had been relatively isolated from the rest of the continent due to its geography.
- However, in the 15th century, Portuguese explorers began to venture out into the Atlantic Ocean, seeking new trade routes and territories.
- One of the most famous of these explorers was Vasco da Gama, who set out in 1497 with four ships and a mission to reach India.

Arrival in India:
- After a long and treacherous journey around the southern tip of Africa, Vasco da Gama arrived in Calicut (now Kozhikode) on the southwest coast of India in May 1498.
- He was greeted by local merchants who were interested in the goods he had brought from Europe, such as silver, gold, and coral.
- Da Gama established a trading post in Calicut and negotiated with the local ruler for permission to trade in spices and other goods.
- Over the next few decades, other Portuguese explorers and traders followed in da Gama's footsteps, establishing more trading posts and forts along the coast of India.

Impact:
- The Portuguese presence in India had a significant impact on the region, both economically and culturally.
- They monopolized the spice trade and other valuable commodities, which gave them great wealth and power in the region.
- They also introduced new technologies and ideas, such as firearms and Christianity, which had a lasting impact on Indian society.
- However, their aggressive tactics and attempts to convert Indians to Christianity also led to conflict with local rulers and resistance from the population.

Overall, the arrival of the Portuguese in India marked the beginning of European colonialism in the region and had far-reaching consequences for both India and Europe.