According to “History of ‘The Battle Hymn of the Republic,’” why does Julia Ward Howe rewrite the lyrics to “John Brown’s Body”?

A
Howe’s lyrics change the theme to support slavery.
B
Howe’s lyrics change the theme to support abolitionism.
C
Howe’s lyrics maintain the theme but add a more uplifting message.
D
Howe’s lyrics maintain the theme but make the song easier to remember.