The capital of Bosnia-Herzegovina, Sarajevo's population on the eve of the First World War was 51,919.
(A) Bosnia-Herzegovina, Sarajevo's population
(B) Bosnia-Herzegovina is Sarajevo, whose population
(C) Bosnia-Herzegovina is Sarajevo, with a population
(D) Bosnia-Herzegovina, Sarajevo having a population that
(E) Bosnia-Herzegovina, the population of Sarajevo

Ans is B
My question is whose can refer to Sarajevo or whose can also refer to Bosnia-Herzegovina ,thewn how cum ans is B