Based on the biological classifications provided in the sources, option B is correctly categorised with a valid exception:

• Items & Category: Plasmodium and Trypanosoma are both identified in the sources as protozoan parasites; Trypanosoma is a flagellated protozoan and Plasmodium is a sporozoan .
• Exception: Cuscuta is identified as a member of Kingdom Plantae and is a parasitic plant . While all three items are parasites, Cuscuta is the exception because it is not a protozoan. Other options are incorrect because: Option A: All three (Kangaroo, Koala, Wombat) are Australian marsupials [outside of sources; Kangaroo/Macropus is noted as a mammal in 273], so Wombat is not an exception. Option C: Typhoid and Pneumonia are confirmed as bacterial diseases , and Diphtheria is also a known bacterial disease often grouped with them ; thus, there is no exception to the category.
• Option D: The sources explicitly state that UAA, UAG, and UGA are all stop (terminator) codons , meaning UAG is not an exception to that category.