The correct answer is C. Fulfil. The correct spelling is fulfill.
- Careful: The word "careful" is spelled correctly. It means to be cautious and attentive to detail.
- Untill: The word "until" is spelled correctly. It means up to the time that.
- Final: The word "final" is spelled correctly. It means last or conclusive.
- Fulfil: The word "fulfil" is spelled incorrectly. The correct spelling is "fulfill." It means to carry out or complete something.
