Answer:
C. To replace Moscow, which had been destroyed in war.
Explanation:
Peter make St. Petersburg the capital of Russia because
- founder, Peter, hated Moscow because of bloody struggle for succession
- Peter saw it as paradise
- access to water
- it was closer to the sea
,
- needed a fresh start that he had control over
, and
- intended it as a model for Russia
SO, it's "C".