HIV's genome of RNA includes code for reverse transcriptase (RT), an enzyme that acts early in infection to synthesize a DNA genome off of an RNA template. The HIV genome also codes for protease (PR), an enzyme that acts later in infection by cutting long viral polyproteins into smaller, functional proteins. Both RT and PR represent potential targets for antiretroviral drugs. Drugs called nucleoside analogs (NA) act against RT, whereas drugs called protease inhibitors (PI) act against PR.


Which of these represents the treatment option that is most likely to avoid the production of drug-resistant HIV (assuming no drug interactions or side effects)?
a. using a series of NAs, one at a time, and changed about once a week
b. using a single PI, but slowly increasing the dosage over the course of a week
c. using high doses of NA and a PI at the same time for a period not to exceed 1 day
d. using moderate doses of NA and of two different PI's at the same time for several months