A is wrong. It should be "In the trunk of the car is a first-aid kit and a blanket." B is wrong. It should be "On the other side, walk down the alley and turn left." C is wrong. It should be "If she asks, ask her why she did it."
Note that in B and C the parts after the comma are sentences on their own, however the part in A was not.
It is not clearly shown the underlined sentence but I will identify the all the parts of the sentence
The patient is the subject, showed is the verb, the dentist is the indirect object and her sore tooth is the direct object. I except your question was this