The first blank needs 'carriers' (plural, meaning agents that transmit disease). The second blank needs 'career' (profession or occupation). Only option 3 provides the correct spellings for both words. Other options contain misspellings.
Note: The NTA question labels these as homonyms, but 'carrier' and 'career' are not true homonyms. We have chosen the option with correctly spelled words that fit the blanks.