What is the term used to describe the transfer of genetic material from one bacterium to another with the help of a viral vector?

 Transduction

Transduction is the term used to describe the transfer of genetic material from one bacterium to another through the mediation of a viral vector. During transduction, a bacteriophage (a virus that infects bacteria) infects a donor bacterial cell and incorporates a fragment of the donor's DNA into its own viral DNA. When the bacteriophage subsequently infects another bacterial cell, it delivers this fragment of donor DNA into the recipient cell, where it can integrate into the recipient's genome.

Conjugation, on the other hand, involves the direct transfer of genetic material between two bacterial cells through a physical bridge called a conjugation pilus.

Transformation refers to the uptake of extracellular DNA by bacterial cells, leading to the incorporation of the foreign DNA into the recipient cell's genome.

Translation is a completely different process that occurs during gene expression, where the genetic information in mRNA is used to synthesize a specific protein.

Therefore, the correct answer is:

(a) Transduction