Which of the following is the correct sequence of the Islands of Indonesia from West to East ?

Read the islands from the western tip of the archipelago eastward. Sumatra is the westernmost, spanning roughly 95°E to 106°E. Java lies next, roughly 105°E to 114°E, separated from Sumatra by the Sunda Strait. Bali sits just east of Java at about 115°E, and Lombok lies further east at about 116°E, separated from Bali by the Lombok Strait. The sequence is Sumatra, Java, Bali, Lombok, which is option B.

• A is wrong because Java is placed west of Sumatra.
• C is wrong because Lombok is placed before Bali, and Bali is west of Lombok.
• D is wrong because Bali is placed west of both Sumatra and Java.

The core concept is the east-west spread of the Indonesian archipelago, which runs along the equator for over 5,000 km. The Lombok Strait between Bali and Lombok is also a key marker of the Wallace Line, the biogeographic divide between Asian and Australasian fauna. That connects this to physical geography of Asia and to Mains questions on island biogeography.

Trap: Candidates place Java west of Sumatra because they picture the Java island chain first on a map.