(A) : Bubonic plague is basically a blood disease.
(R): The bacteria multiply in the blood stream and localize in the lymph nodes.
A. If both (A) and (R) are true and (R) is the correct explanation of (A).
B. If both (A) and (R) are true but (R) is not the correct explanation of (A).
C. If (A) is true but (R) is false.
D. If both (A) and (R) are false.