The structure used for sexual contact between bacteria is/are:

Explanation

Pili (singular: pilus) are hair-like appendages on the surface of bacteria. They are involved in various functions, including attachment to surfaces and bacterial motility. However, some bacteria also possess a specific type of pilus called a sex pilus or F pilus. Sex pilus is involved in a process called bacterial conjugation, which is a form of sexual contact between bacteria. During conjugation, a donor bacterium transfers a plasmid (often containing antibiotic resistance genes) to a recipient bacterium through the sex pilus. Therefore, the correct option for the structure used for sexual contact between bacteria is D) Pili.