{"answers": "D", "options": ["f : what ? one square kilometer can grow about 1500 trees ? that 's a lot .", "f : i see . we can plant about 400 trees in one square kilometer , right ?", "f : i see . we can plant about 750 trees in one square meter , ca n't we ?", "f : so one square kilometer can grow about 750 trees , right ? that 's a lot ."], "article": "f : so , here we are . deep in the forest . with me is doctor mike green . doctor green can you tell us a little about this wonderful place ? m : yes , of course , as you can see , the forest is full of trees , birds and insects . f : yes , there are some strange and beautiful plants everywhere . how many different kinds of plants are there ? m : well , in just one square kilometer of the forest , you can find about 1500 different kinds of plants , and many of those 1500 kinds of plants do n't grow in any other place in the world . f : and there are hundreds of trees too , are n't there ? m : yes , there are . in fact , there are about 750 different kinds of trees in one square kilometer .", "id": "train_3722"}