What is the "miracle" in Bede's "Caedmon's Hymn"?

What is the “miracle” in Bede’s “Caedmon’s Hymn”?

A. Caedmon witnesses the birth of Christ.
B. Caedmon turns water into wine.
C. The abbess sees an apparition of the Virgin Mary.
D. Caedmon gets the gift of song and poetry.