The correct options are
A The war lasted a total of 26 years, with an estimated death toll of over a lakh
B The Sinhala Only Act, 1956, declared Sinhalese as the official language of Sri Lanka
C Militant groups demanded the creation of a separate Tamil state in Sri Lanka
Religious, ethnic, and linguistic conflict between the minority Tamils and the dominant Sinhalese in Sri Lanka led to a long period of civil strife. The war broke out on July 1983, since then called 'Black July', when Tamils were attacked in riots in Colombo. The 'Liberation Tigers of Tamil Eelam' was a group formed to represent the Tamils. This was a militant group which demanded a seperate Tamil state in Northeastern Sri Lanka.