"Die Hexe hat einen Zauberspiegel" should also be accepted.
Why is mirror plural~!! Thw witch as A magic mirror, right?
Die Hexe hat eine magische Spiegel. One mirror, not mirrors.
Spiegel is singular here, but it is masculine, so in the accusative case, "ein" (masculine indefinite singular) becomes "einen". As the article is "einen", the adjective after must agree, so -en is added to "magisch".
The distractors are too easy again? Who ever would confuse Külshcrank with Spiegel?
Our feathered friend doesn't like
Die Hexe besitzt einen magischen Spiegel.
Any ideas why not?