Laldenga was the leader of:

Mizo National Front

The correct answer is option (3) - Mizo National Front

After Independence, the Mizo Hills area was made an autonomous district within Assam. Some Mizos believed that they were never a part of British India and therefore did not belong to the Indian union. But the movement for secession gained popular support after the Assam government failed to respond adequately to the great famine of 1959 in Mizo hills. The Mizos’ anger led to the formation of the Mizo National Front (MNF) under the leadership of Laldenga.

Laldenga (1937-1990) founded and led the Mizo National Front. Laldenga's transformation into a rebel leader was catalyzed by the severe famine of 1959. Frustrated by the inadequate response of the Indian government, he took up arms and led an armed struggle against India that persisted for two decades. This struggle aimed to secure greater autonomy and recognition of Mizo identity.