which sentence is punctuated correctly 1 point

1 Dee passed her math test with a perfect score: she studied all week long.
2 Dee passed her math test with a perfect score: her favorite color is blue.
3 Dee passed her math test with a perfect score, she got all the answers correct.
4 Dee passed her math test with a perfect score: she got all the answers correct.

Sentence 1 is punctuated correctly.