The correct answer is - A. Electricity.
Russia is a country that has an abundance of natural resources, and it uses them in order to produce its own electricity, and does it multiple ways. As one of the countries that has developed nuclear programs from long time ago, Russia has also used this technology in order to build nuclear reactors for the production of electricity. Also, the country has numerous rivers that are very large in every aspect, so lots of hydroelectric capacities have been built in the dams for production of electricity. The fossil fuels are also used on a big scale, and the usage of coal and mazut in the generators for producing electricity is still big.