Why Were Russian Leaders So Keen to Gain Territory in Southeastern

Why were Russian leaders so keen to gain territory in southeastern Europe, even though it drew Russia into conflict with the Ottoman Empire?

A) It would support Russians living in Turkey.
B) It would give them access to oil reserves.
C) It would allow them to remain in compliance with a treaty with Greece.
D) It would make up for the loss of territory to Poland.
E) It would give them access to the Mediterranean Sea by means of a warm-water port.