Which of the following refers to the mechanism of horizontal gene transfer naturally responsible for the spread of antibiotic resistance genes within a bacterial population?

conjugation

generalized transduction

specialized transduction

transformation

The correct answer is option conjugation.

Explanation:s

Horizontal gene transfer is also called lateral gene transfer. It involves transfers of genetic material of an organism in to another organism that is not its progeny.

This process is characteristic feature of bacteria and archaea. Gene transfer is takes place in three ways transduction, transformation and conjugation. Conjugation is the the type of horizontal which occurs naturally especially in between donor and recipients.

Thus, the correct answer is option Conjugation.