When the republic of california declared independence from mexico, the us government

sent troops to make it part of the united states.
sent a diplomat to offer money to annex california.
continued to fight the mexican-american war.
decided to annex other republics instead.

  Sent a diplomat to offer money to annex California.

Explanation:

  The Republic of California began when a group of American immigrants rebelled against the Mexican government in Alta California. The rebellion was encouraged in secret by the U.S. Army and it happened when the Mexican-American war was beginning.

  The rebellion began in June and in November the President sent a diplomat to Mexico in order to present an offer to purchase California and New Mexico. But the mission failed.

  I hope this answer helps you.