Answer: C. Congregational singing
Explanation: Congregational singing is the practice of the congregation joining in the music of a church, either in the form of hymns or in the form of the office of the liturgy. Several reasons why congregational singing is so important in the life of a church are:
1. It unifies the congregation
2. It is a great way to praise the lord
3. It is a wonderful way to pray together.
4. It solidifies and teaches spiritual truth.
5. It can aid in revival