I would be inclined to say C, Mediterranean climate zone. Due to the fact that Desert climate would not grow grass without insane amounts of irrigation being used ( although there have been dairy farms in desert climates). Highland climates would be good, but too vulnerable to snow especially depending on location globally, although they would get a good rainfall, but the cold would limit grass growth. Most of this is also true for subartic. Whereas Mediterranean is mild winters with good rainfall, and summers are often dry (good for harvesting crops) much of this climate zone has already been developed for agricultural use.
