Hildegard von Bingen is remembered for: A. her polyphonic motets.
B. the musical play Jeu de Robin et de Marion.
C. developing new methods of musical notation.
D. her mystical compositions.

D. her mystical compositions.

Explanation:

Hildegard von Bingen or Saint Hildegard was a German nun, composer, mystic, and philosopher. Some consider her as the founder of scientific natural history in Germany as she wrote many pieces on botanical and medical science based on scientific evidence, diagnosis, and treatment.

She is also regarded as the first composer to whom we can attribute pieces for sure. While some of her music is lost, plenty is saved and played even today.

Ordo Virtutum is one of the most famous ones, and it is also the first morality play that is known. It presents the accounts of her visions and allegory of the story of Christian sins.

Mysticism is the state of religious ecstasy and spiritual alternative state of consciousness. As Hildegard von Bingen composed about her visions of God and the saints, her famous work is considered to be mystical.