All are circular DNA EXCEPT:

Nuclear REF: Jawetz's 24th edition chapter 7 The Eukaryotic Genome The genome is the totality of genetic information in an organism. Almost all of the eukaryotic genome is carried on two or more linear chromosomes separated from the cytoplasm within the membrane of the nucleus. Eukaryotic cells contain mitochondria and, in some cases, chloroplasts. Within each of these organelles is a circular molecule of DNA that contains a few genes whose function relates to that paicular organelle. Most genes associated with organelle function, however, are carried on eukaryotic chromosomes. Many types of yeast contain an additional genetic element, an independently replicating 2-m circle containing about 6.3 kbp of DNA. Such small circles of DNA, termed plasmids, are frequently encountered in the genetics of prokaryotes. The small size of plasmids renders them amenable to genetic manipulation and, after their alteration, may allow their introduction into cells. Therefore, plasmids are frequently called upon in genetic engineering.