Which of the following events is most likely due to bacterial transformation?

  •   A strain of Neisseria gonorrhoeae starts producing a plasmid-encoded beta-lactamase similar to that another Gram-negative strain.
  •  A formerly non-toxigenic strain of Corynebacterium diphtheriae becomes toxigenic.
  •   A gene for gentamicin resistance from an Escherichia coli chromosome
  •   A non-encapsulated strain of Streptococcus pneumoniae acquires a gene for capsule formation from the extract of an encapsulated strain.