A Strain of Penicillin-Resistant N

A strain of penicillin-resistant N.gonorrhoeae that does not have a plasmid is isolated.A lysate made from the bacterium cannot degrade penicillin in an in vitro assay.When a culture of this strain is grown in a solution that contains radioactive penicillin, the amount of penicillin found within cells is less than the amount found within cells from a nonresistant strain.The DNA sequence of the porin gene from the resistant strain does not have any mutations.What is the most likely mechanism of resistance in this strain?

A) A mutation in the mtr gene has occurred, resulting in fewer efflux pumps.
B) A penA nonsense mutation has occurred.
C) A penA missense mutation has occurred.
D) The bacterial genome carries the pen^r gene.