The correct options are
B The workers stopped the train in which the Tsar was returning to Petrograd.
C The Tsar ordered a declaration of martial law, but nobody obeyed his orders.
The Tsar Nicholas II ordered a declaration of martial law, but there was nobody to broadcast his order. The Tsar then tried to return to Petrograd but railway workers stopped his train. The generals and leaders of Petrograd advised the Tsar to give up his powers. On 15 March, Nicholas II formally left the throne.