Answer:
Letter C is the correct answer.
Step-by-step explanation:
Gregorian chant was developed in Central and Wester Europe around the 10th Century. Monophony, a musical texture distinguished by its simplicity, is one of its main characteristics. Gregorian chant is also used in liturgies by the Roman Church, specially in the West. Some of the texts are taken from the Bible and others are related to specific moments of the day (like the Angelus), so the text is sacred. It is also sung a cappella, meaning that voice is the only instrument.