The correct option is A Violent conflicts with LTTE
The Indian Peace Keeping Force was sent to Sri Lanka in 1987 to end the Sri Lankan Civil War between the Tamil minority groups such as the Liberation Tigers of Tamil Eelam (LTTE) and the Sinhalese group. The Indian Peace Keeping Force eventually ended up in a battle with the LTTE to enforce peace - a move that was accepted by neither the Tamils nor the Sri Lankan government. So, it was withdrawn in 1989 and 1990.