Pathogens

Step 1: Correct identification of disease and pathogen.
Syphilis is caused by the bacterium Treponema pallidum.
Therefore, option (B) is correct.
Step 2: Review of other options.
AIDS is caused by HIV, not a Bacillus.
Malaria is caused by Plasmodium, not Trypanosoma (which causes sleeping sickness).
Gonorrhoea is caused by the bacterium Neisseria gonorrhoeae, not a virus.
Thus, the correct answer is (B) Syphilis - Treponema Pallidum.