The thermostable enzyme , ''Taq'' and ''Pfu'', is isolated from thermophilic bacteria are :

Options

A. DNA ligases
B. RNA polymerases
C. DNA polymerases
D. Restriction endonucleases

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about thermostable enzymes, specifically "Taq" and "Pfu", which are isolated from thermophilic bacteria.

2. **Identifying Thermostable Enzymes**: Thermostable enzymes are those that can function at high temperatures. Taq polymerase is derived from the bacterium *Thermus aquaticus*, and Pfu polymerase is derived from *Pyrococcus furiosus*. Both are known for their stability and activity at elevated temperatures.

3. **Recognizing the Function of Taq and Pfu**: Both Taq and Pfu are types of DNA polymerases. Their primary function is to synthesize new strands of DNA during processes like the Polymerase Chain Reaction (PCR).

4. **Analyzing the Options**: The options provided are:
- DNA ligases
- RNA polymerases
- DNA polymerases
- Restriction endonucleases

Among these, DNA polymerases are the enzymes that match the description of Taq and Pfu.

5. **Eliminating Incorrect Options**:
- **DNA ligases**: These enzymes join DNA fragments together but do not synthesize DNA.
- **RNA polymerases**: These synthesize RNA from a DNA template, not DNA itself.
- **Restriction endonucleases**: These cut DNA at specific sites but do not synthesize it.

6. **Conclusion**: The correct answer is DNA polymerases, as Taq and Pfu are both thermostable enzymes that perform DNA polymerization.

**Final Answer**: DNA polymerases.

---