It is because of sufficient dairy products as a source of food that herders living in the Hulunbuir steppe can ingest sufficient calcium. Obviously, this sufficient calcium is essential for herdsmen in hulun buir grassland to have a strong body. Which of the following conditions, if true, would weaken the above assertion best? ['Some herdsmen of the Hulunbuir Prairie do not have a strong physique, but the calcium intake from food is quite a lot.', 'Some herdsmen in the Hulunbuir Prairie do not have a strong physique and they cannot take enough calcium from food.', 'Some herdsmen of the Hulunbuir Prairie have a strong physique but do not have enough dairy products as a source of food.', 'Some herdsmen in the Hulunbuir Prairie do not have a strong physique, but have sufficient dairy products as a source of food.']