Correct Answer: curtesy

Solution : The correct choice is the fourth option.

Explanation : In this case, the correct spelling of the word relating to polite behaviour or gesture is courtesy. The wrongly spelt word is curtesy. The term should be spelled courtesy. The error is that there should be an o after c. It's essential to note that curtesy is not a recognised spelling, and the correct spelling pertains to manners and politeness.

Therefore, the correct spelling of the word is courtesy .