Which one of the following cannot be used for preparation of vaccination against plague ?

Options

A. Formalin-inactivated suspensions of virulent bacteria
B. Avirulent live bacteria
C. Synthetic capsular polysaccharide material
D. Heat-killed suspensions of virulent bacteria

Answer

C

Explanation

Synthetic capsular polysaccharide vaccines are available for the treatment of pneumonia caused by streptococcus pneumoniae.