Which sentence uses correct punctuation?

Voltaire wrote this about personal freedom, “I disagree with what you say and will defend to the death your right to say it.”

Rachel finally decided on a major for college, physics.

We saw several national landmarks on our summer vacation: Mount Rushmore, the Washington Monument, and the Grand Canyon.

For my history paper, I chose three key American battles, Lexington, Gettysburg, and Bull Run.

All of the sentences use correct punctuation.