Which one of the following is the largest coal producing centre of Ukraine?

The Donets Basin, commonly known as the Donbas, located in eastern Ukraine, is one of the most significant coal-mining regions in Europe. Donetsk is the largest city and the primary industrial center within this basin. The region's economy has historically been built around its vast coal reserves, particularly high-grade anthracite and bituminous coal. While other cities mentioned are major industrial hubs, their specializations differ: Kharkiv is known for heavy machinery and electronics, Zaporizhzhia is a major center for metallurgy and power generation (hydroelectric and nuclear), and Kyiv is the administrative and political capital. Consequently, Donetsk is the preeminent coal-producing center of the country.