In which one of the following countries is Tamil an official language

In which one of the following countries is Tamil an official language ?

Singapore
Indonesia
Malaysia
Thailand
This question was previously asked in
UPSC CISF-AC-EXE – 2017
Tamil is one of the official languages in Singapore.
Singapore has four official languages: English, Malay, Mandarin, and Tamil.
Tamil is also an official language in Sri Lanka and has significant recognition in Malaysia. It is a Dravidian language spoken by the Tamil people of India and the Tamil diaspora.