Which one of the following is a city name? Luxembourg, Sakaka, Ukraine, Bulgaria

Which one of the following is a city name? Luxembourg, Sakaka, Ukraine, Bulgaria

شہر کا نام مندرجہ ذیل میں سے کون سا ہے؟
Explanation

Sakaka is a city in Saudi Arabia, specifically the capital of Al-Jawf Province.

Luxembourg, Ukraine, and Bulgaria are all countries, not cities.