Step 1: Concept
Reverse transcriptase is an enzyme primarily found in retroviruses that reverses the usual flow of genetic information.
Step 2: Meaning
It uses an RNA template to synthesize a complementary DNA (cDNA) strand.
Step 3: Analysis
Because it "reads" RNA and "writes" DNA, it is classified as an RNA-dependent DNA polymerase. It also typically possesses RNase H activity to degrade the original RNA template.
Step 4: Conclusion
The primary defining activity is RNA-dependent DNA polymerization.
Final Answer: (C)