The correct option is B in a cold region.
The last sentences of the passage talk about "one of us has a bad attack of snow- blindness in one eye", indicating the author in the middle of a storm in a cold region where it is snowing. Option A) desert is incorrect and there is no snow in a desert. Option C)mountains is incorrect as there is no mention of the same and not all mountains have snow fall. Option D) is incorrect as well since it cannot snow at sea level. Therefore ,the correct answer is option B) in a cold region.