The correct answer is - b. Russia.
According to the presented map, the colder climate types, sub-arctic and tundra climates, can be found on the territory of the largest country in the world, Russia. This types of climates are considered as cold climates, and they fully justify that. The tundra, is a climate where most of the year is winter, a very cold, dry, harsh winter, and relatively cold and short summer. The sub-arctic, or taiga, climate has a winter that lasts for pretty much 3/4 of the year, and summer that is fresh, wet, and humid.
Even though the tundra has longer winter, and is located further north than the sub-arctic climate, it is actually the sub-arctic climate that has the bigger extremes in the temperatures bellow zero. Some places in Siberia are so cold, that they are shoulder to shoulder with the most extreme temperatures on the Antarctic.
