Option 1: Malaysia - Malaysia is a member of the Commonwealth. The Commonwealth is a voluntary association of 54 countries, mostly former territories of the British Empire, that cooperate on various issues.

Option 2: Sri Lanka - Sri Lanka is a member of the Commonwealth. It gained independence from British colonial rule in 1948 and joined the Commonwealth the same year.

Option 3: Indonesia - This is the correct answer. Indonesia is not a member of the Commonwealth. It gained independence from Dutch colonial rule in 1945 and has never been part of the British Empire.

Option 4: Singapore - Singapore is a member of the Commonwealth. It gained independence from British colonial rule in 1965 and joined the Commonwealth the same year.

Therefore, the correct answer is option 3, Indonesia, as it is not a member of the Commonwealth.