Experts please answer....
Dear Student,
Plasmid is a circular, extra-chromosomal DNA present in some bacteria. It is used is a vector for carrying out transformation experiments since it contains an origin of replication(ori site, essential for initiation of replication) and other antibiotic resistance genes that aid in identification of transformants.
Plasmids are generally found in prokaryotes, mainly bacteria.
Hence, option D is correct.
Regards