Question

Yersinia pestis is used as a biological weapon. It causes a disease:
A) Smallpox      
B) Plague
C) Tularemia     
D) Anthrax             
 

Answer 1

 Hint: It causes an infectious and deadly disease that affects humans and animals. This bacteria is found in rodents and their small jumping insects and occurs in many areas of the world. yersinia pestis is easily destroyed by drying in sunlight. It caused an epidemic (a large number of people suffering from a disease at a time ) in Europe.
                                                                                    
Complete step-by-step answer:. 

yersinia pestis is used as a biological weapon as it causes plague and plague kills millions of people. So as a biological weapon yersinia pestis can be used. Plague is rare nowadays but causes a serious bacterial infection that is transmitted by fleas(small jumping insects). The bacteria yersinia pestis causes plague. 
The plague is called as Black death during older times. It can be deadly if not treated properly with antibiotics and medicines. The most common form of plague results in buboes-swollen lymph nodes in the groin, armpits, or neck. It is transmitted through infected fleas and their contact. Its symptoms are swollen lymph nodes, which can be very large, in the groin, armpit, or neck. Others symptoms include muscle pain, fatigue or tiredness, headache, and chills.
Anthrax is also a biological weapon and this is caused by the bacterium Bacillus anthracis

The bacteriumFrancisella tularensis  causes tularemia is a rare infectious disease . It is also called rabbit fever.

Variola virus causes smallpox. This can spread from one person to another. You can catch the smallpox virus by being around someone having smallpox. 

Hence the correct answer is option (B) plague.

Note: Biological weapon also called biological warfare or germ warfare, is the use of toxins or infection-causing agents like bacteria, viruses, insects, and fungi with the same intention to kill, harm, or disable humans, animals or plants as an act of war. So these bacteria which cause deadly diseases can be used as a weapon in war as they may kill or weaken the people.