The Following Questions Refer to the Following Paragraph

Multiple Choice

The following questions refer to the following paragraph.
HIV's genome of RNA includes the 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.
-Within the body of an HIV-infected individual who is being treated with a single NA, and whose HIV particles are currently vulnerable to this NA, which of these situations can increase the virus' relative fitness?
1) mutations resulting in RTs with decreased rates of nucleotide mismatch
2) mutations resulting in RTs with increased rates of nucleotide mismatch
3) mutations resulting in RTs that have proofreading capability

A) 1 only
B) 2 only
C) 3 only
D) 1 and 3
E) 2 and 3