The correct option is A 1948
Sri Lanka achieved its independence from British Empire on 4th February 1948 and became Dominion of Ceylon. It was then known as British Ceylon. Dominion status under British Commonwealth was for 24 years, later it turned into Republic of Sri Lanka on 22nd May 1972. D. S. Senanayake of United National Party (UNP) was the first Prime Minister of Ceylon. Option A 1948 is the correct answer.