Choose the correct sentence which is built from the words and phrases given:
It/ has/ estimated/ more/ thousand/ refugees/ pouring/ countryside/ town/ in search/ food.
It has estimated that more than a thousand refugees pouring from the countryside into the town in search of food.
It has been estimated that more than a thousand refugees are pouring from the countryside into the town in search of food.
It has been estimated that more thousand refugees are pouring from the countryside into the town in search for food.
It has estimated that more than thousand refugees are pouring from the countryside to the town in search of food.
It has been estimated that more than a thousand refugees are pouring from the countryside into the town in search of food.