Why did Rajiv Gandhi order the deployment of the Indian Army to Sri Lanka in 1987?

To assist the Sri Lankan government in addressing the Tamil insurgency

The correct answer is Option 1 - To assist the Sri Lankan government in addressing the Tamil insurgency

Rajiv Gandhi ordered the deployment of the Indian Army to address the Sinhala-Tamil conflict in Sri Lanka, following the Sri Lankan government's request for assistance in dealing with the Tamil insurgency.

Rajiv Gandhi (1944–1991):
Served as the Prime Minister of India from 1984 to 1989;
The son of Indira Gandhi, he entered active politics after 1980;
Successfully negotiated agreements with militants in Punjab, Mizoram, and the student union in Assam;
Advocated for economic liberalization and the adoption of computer technology;
Ordered the deployment of an Indian Army contingent to address the Sinhala-Tamil conflict in Sri Lanka, following the Sri Lankan government's request;
Tragically assassinated by a suspected LTTE suicide bomber.