What is the official currency of Kuwait?

The official currency of Kuwait is the Kuwaiti Dinar, and the correct answer is C, Kuwait, as it directly refers to the country where this currency is used. Each country has its own official currency that is recognized for transactions within its borders. In the case of Kuwait, the dinar is not only a legal tender but is also noted for being one of the highest-valued currencies in the world.

The other options refer to different countries that each have their own unique currencies but are not related to Kuwait's official currency. Portugal uses the Euro, Colombia uses the Colombian Peso, and Sudan uses the Sudanese Pound. Each of these currencies operates within their respective economies and does not apply to the context of the question regarding Kuwait.