The correct answer is option 4 - Chili. The Portuguese were the first Europeans to arrive in India in the 15th century and they introduced several crops to the region during their colonization.

Option 1 - Opium was not introduced by the Portuguese in India. Opium has a long history in India and was cultivated and used for medicinal and recreational purposes even before the arrival of the Portuguese.

Option 2 - Coffee was not introduced by the Portuguese in India. Coffee cultivation and consumption in India dates back to the 17th century when it was brought by Baba Budan, a Sufi saint, from Yemen.

Option 3 - Betel leaf was not introduced by the Portuguese in India. Betel leaf is native to South and Southeast Asia and has been used in India for centuries for chewing and religious rituals.

Therefore, option 4 - Chili is the correct answer. The Portuguese introduced chili to India, and chili cultivation spread throughout the country. It has since become a staple ingredient in Indian cuisine.