The correct answer is option 4, Turkmen desert.

First, let`s understand what a temperate desert is. A temperate desert is a type of desert that occurs in regions with moderate temperatures. These deserts are usually found in the mid-latitudes, far away from the equator.

Now, let`s analyze each option provided:

1) Patagonian desert: The Patagonian desert is located in South America, primarily in Argentina and Chile. Although it is a large desert, it is not considered a temperate desert. Therefore, this option is incorrect.

2) Taklamakan desert: The Taklamakan desert is a desert located in northwest China. It is one of the largest deserts in the world, covering an area of about 270,000 square kilometers. However, it is not a temperate desert. Therefore, this option is incorrect.

3) Iranian desert: The Iranian desert is a combination of several deserts located in Iran, including the Dasht-e Kavir and the Dasht-e Lut. While it is a large desert, it is not classified as a temperate desert. Therefore, this option is incorrect.

4) Turkmen desert: The Turkmen desert, also known as the Karakum