Which sentence uses a semicolon correctly?

(Remember, a semicolon joins two complete sentences.)

And not only did she know in which room stood the lady ready to emerge; all blushing and radiant.

The king had a daughter as blooming as his most florid fancies; her soul was fervent and imperious.

Should her door be opened; but she knew who the lady was.

The king had a daughter as blooming as his most florid fancies; her soul was fervent and imperious.