TASK DEFINITION: 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.
PROBLEM: A frosbee is in the sky over a grassy field.

SOLUTION: frosbee

PROBLEM: A whote toilet sitting under a water tank.

SOLUTION: whote

PROBLEM: A bixycle leaning against a tree off a riverbank.

SOLUTION:
bixycle