A cat might be a good pet for a teen, especially it the teen has never been responsible for one. It'll go in a box; the parents will probably have to tell the teen when to clean it. The cat won't require the attention a dog will as cats usually like to keep to themselves (at least for the most part), they don't require being taken for a walk.
Teens tend to be forgetful of chores and 'on the go' and parents often end up keeping up with the pet. I can't tell you how many parents I know who manage the day to day upkeep of their children's pets. Just try getting a teen to talk the dog for a morning walk in the rain before school. It can happen but it is a challenge!