Answer:
Conjugation pilus
Step-by-step explanation:
Pili are structures found in bacterial cells, extending from the cell wall. The conjugation pili allows one bacterium to connect to another and transfer DNA.
It is through the pilus that genetic information is transmitted. For example, genetic factors for antibiotic resistance or virulence (the ability of a bacterium to cause disease) found in plasmids.
As explained above, it is concluded that the structure representing the pilus in the attached image is D.