| LIST I | LIST II |
|---|---|
| A. Bhutan | I. The first country to liberalise its economy in South Asia |
| B. Maldives | III. An island nation, was sultanate till 1968 |
| C. India | II. Centrally located and shares borders with most of the South Asian countries |
| D. Sri Lanka | IV. A land nation, was sultanate till 1968 |
What comes next in the series?
\(2, 6, 12, 20, 30, \ ?\)