Choice A rationale:

Antibiotics such as ceftriaxone or cefixime.

Antibiotics are used to treat bacterial infections, not viral infections.

Genital blisters or ulcers are commonly associated with herpes simplex virus (HSV) infection, which is a viral infection.

Therefore, antibiotics like ceftriaxone or cefixime would not be effective in treating this symptom.

Choice B rationale:

Antibiotics such as azithromycin or doxycycline.

Similar to Choice A, these antibiotics are used to treat bacterial infections, and they would not be effective against viral infections like genital herpes.

Genital herpes is caused by the herpes simplex virus (HSV), which requires antiviral medications for treatment.

Choice C rationale:

Antiviral medications like acyclovir, valacyclovir, or famciclovir.

This is the correct choice.

Antiviral medications such as acyclovir, valacyclovir, or famciclovir are commonly used to treat symptoms of genital herpes, including painful blisters or ulcers.

These medications work by inhibiting the replication of the herpes virus, reducing the severity and duration of symptoms.

Choice D rationale:

Penicillin G for antibiotic therapy.

Penicillin G is an antibiotic used to treat bacterial infections, particularly syphilis.

However, it is not effective against viral infections like genital herpes.

Therefore, it is not the appropriate choice for treating the symptoms described in the question.