The correct answer is - D. None.
Russia's agriculture is not focused on the permanent croplands at all, in fact they are so rare that it seems that they are totally absent in this vast country. The actual percentage of permanent cropland in the Russian Federation is 0.977%, so less than 1%.
The plants considered to be part of the permanent croplands are the plants that do not need to be replanted or seeded every year, bu they are existing for longer periods of time. In this type of plants are included the fruit trees, flowering shrubs, vines, and the nut trees.
Russia's focus though is not on this type of plants, but it is almost entirely focused on seasonal crops, such as the wheat for example.