The given sentence contains a typo which could be one of the following four types: (1) swapped letters of a word e.g. 'niec' is a typo of the word 'nice'. (2) missing letter in a word e.g. 'nic' is a typo of the word 'nice'. (3) extra letter in a word e.g. 'nicce' is a typo of the word 'nice'. (4) replaced letter in a word e.g 'nicr' is a typo of the word 'nice'. You need to identify the typo in the given sentence. To do this, answer with the word containing the typo.

[Q]: A trqain rolling by a mountain stream and trees.
[A]: trqain


[Q]: A blqck cat holding onto the left of a teddy bear.
[A]: blqck


[Q]: A bifg group of people standing on the grass.
[A]:
bifg