Вставьте в пропуск в предложении вариант с правильным ответом!

Apple __________ (CURRENTLY, WORK) on new features for the iPhone, including improved security measures and enhanced camera capabilities.

Варианты ответов:

1) currently works
2) currently working
3) are currently working
4) is currently working
5) is currently worked

В ответ впишите только цифру, обозначающую вариант ответа!