Take a look at the passage again:
To keep the cat from sleeping on her new convertible's canvas top.
Kim leaves the garden hose out. Like a gunslinger
in a Western, she "duels" with Rocky, the family's orange tom, who hisses
as vehemently as the forceful spray of water.
You chose the second part, Kim leaves the garden hose out. This part has a main clause: Kim is the subject; leaves is the verb. A fragment will not have a main clause.
Go back to the passage to try again.