Transduction in bacteria is carried out by
a. Bacteriophage
b. Blue-green algae
c. Mycoplasma
d. Rickettsiae

Hint: Transduction is also called horizontal gene transfer, where it is the process by which a foreign DNA is introduced into the cell, for example, viral transfer of DNA from one bacteria to another bacteria.

Complete answer:
- The transduction process does not require the contact of Donor and recipient cells like in conjugation.
- Where it is the type, where modern biologists use this process to introduce foreign DNA into host genome cells.
- The particles which help for transferring the DNA in the process of transduction are called Phages or bacteriophages.
- Transduction occurs in two types, they are general transduction and specialized transduction.
- Transduction happens either through lytic or lysogenic cycles.
- In generalized transduction, the random pieces of the bacteria DNA are packed into the Phages, and this is happening mainly in the lytic cycle.
- When coming to specialized transduction, in this type only specific genes are transferred from one bacteria to another.
- There is another type of transduction called lateral transduction, where one big template of bacterial DNA strand is transferred from one to another, generally, this type of transduction is not seen at all, it is seen only in the Staphylococcus.
- Mostly these transfers are done by viruses or viral particles, viruses are called bacteriophages.

Hence, the correct answer is option (A).

Note: In recent days, so many scientists use transduction for gene transfer, where they mostly use lentil virus and adenovirus as phages, and some people use phagemids, it has both phage and plasmid properties.