Which famous tune became a "theme song" of the Union army during the Civil War?

A) Lincoln and Liberty
B) I Wish I Was in Dixie
C) The Battle Hymn of the Republic
D) When Johnny Comes Marching

Mine eyes have seen the glory of the coming of the Lord:
He is trampling out the vintage where the grapes of wrath are stored;
He hath loosed the fateful lightning of His terrible swift sword:
His truth is marching on.

Glory, glory, hallelujah!
Glory, glory, hallelujah!
Glory, glory, hallelujah!
His truth is marching on.

I have seen Him in the watch-fires of a hundred circling camps,
They have builded Him an altar in the evening dews and damps;
I can read His righteous sentence by the dim and flaring lamps:
His day is marching on.

Glory, glory, hallelujah!
Glory, glory, hallelujah!
Glory, glory, hallelujah!
His day is marching on.