Multiple copies of an antibiotic resistance gene was found on the chromosome isolated from bacteria X. What is the most likely explanation for this occurrence?

A、MultiplecopiesofanantibioticresistancegenewasfoundonthechromosomeisolatedfrombacteriaX.Whatisthemostlikelyexplanationforthisoccurrence?
B、thebacteriamatedwithnumerousbacteriacontainingplasmidswiththeantibioticresistancegene
C、thebacteriacontainedtheantibioticresistancegeneonatransposonthatunderwentreplicativetransposition
D、thebacteriacontainedmultiplecopiesoftheantibioticresistancegenefromrecombination