Double-decker buses are still extant in some cities of India.

unheeded
forgotten
destroyed
extinguished

The correct answer is: extant.

Extant means still existing or surviving. In this case, it means that double-decker buses are still in use in some cities of India.

The other options are incorrect because they do not mean “still existing or surviving.”

  • Unheeded means not paid attention to.
  • Forgotten means not remembered.
  • Destroyed means ruined or demolished.
  • Extinguished means put out or made to stop burning.