You can name up to three different ones, either all from one author or from different authors. They can be in any genre of fiction that you want- but only of fiction- and their size can also vary (ie you can name a very short story if you want to). It doesnt matter if you have read thousants of books or just a few, you can just name some that you feel were really worth reading 
My choices are: (in no particular order)
The basement (Fyodor Dostoevsky)
The castle (Franz Kafka)
The horla (Guy de Maupassant)

My choices are: (in no particular order)
The basement (Fyodor Dostoevsky)
The castle (Franz Kafka)
The horla (Guy de Maupassant)