Toxins (saxitoxins) secreted by some dinoflagellates enter the body of human beings through food chain and result in

The correct option is B Paralysis
Genus Alexandreum of dinoflagellates secretes neurotoxin saxitoxins which are the causative agents of paralytic shellfish poisoning (PSP). Molluscs such as mussels and clams feed on a large number of dinoflagellates, human consumption of those molluscs causes paralysis.

Madness is a characteristic symptom of rabies which is caused by RNA virus “rabies virus” and is mostly spread through the bite of an infected dog.

Syphilis is a sexually transmitted disease, caused by gram negative spirochete, Treponema pallidum.

Plague is caused by gram negative rod shaped bacteria. Yersinia pestis and is characterised by flu-like symptoms. It is transmitted by bites from infected fleas. So, the correct answer is option B.