Let's analyze each option:
(1) Transfection:
Transfection involves introducing foreign DNA into eukaryotic cells, not into bacteria. It does not involve naked DNA fragments being taken up by bacteria. Hence, this is not the correct answer.
(2) Transformation:
Transformation is the process where bacteria take up naked DNA fragments from their environment. This is the correct answer.
(3) Transduction:
Transduction involves the transfer of bacterial DNA via a bacteriophage (virus), not the uptake of naked DNA. Hence, this is not the correct answer.
(4) Conjugation:
Conjugation involves the transfer of genetic material between bacteria through direct contact, typically involving plasmids. It does not involve the uptake of naked DNA. Hence, this is not the correct answer.
Conclusion:
The correct answer is Option 2: Transformation as it involves the uptake of naked DNA by bacteria.