John, a fourth-grade student, normally talks in a shout. Today, however, he has kept his voice to a comfortable level. Your best response is
A. "John, you behaved well today."
B. "John, you kept your voice level down today. It made the ride very pleasant for all of us."
C. "John, don't you feel well today? You were so quiet."
D. Do not call attention to his behavior since he finally is doing what you expect from all students.