Final answer:
Neisseria gonorrhoeae (Option D) has surface projections that are important in attachment to host cells and are major virulence determinants.
Step-by-step explanation:
The organism described in the question that has surface projections (pili) important in attachment to host cells and are major virulence determinants is Neisseria gonorrhoeae (Option D).
Neisseria gonorrhoeae is the bacteria responsible for the sexually transmitted infection gonorrhea. The pili of Neisseria gonorrhoeae are hair-like structures on the bacterial surface that allow the bacteria to attach to the epithelial cells of the human reproductive tract. By attaching to host cells, Neisseria gonorrhoeae can colonize and cause infection.
Keywords: Neisseria gonorrhoeae, pili, attachment to host cells, virulence determinants