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.

[EX Q]: Chikldren are at the zoo by the giraffes.
[EX A]: Chikldren

[EX Q]: A trqin with a yellow front next to an empty track.
[EX A]: trqin

[EX Q]: A blqck yak standing in a field staring into the camera.
[EX A]:
blqck