The correct answer is C. Occular.
The other three words are spelled correctly.
- Occupation: the act of engaging in a particular activity, especially one that is paid.
- Occur: to happen or take place.
- Occlude: to block or cover up something.
Occular is a word that is not commonly used, and it is possible that some people may not be familiar with it. However, it is a real word that is spelled correctly. It means "relating to the eye or sight."
