--What do you often do          classes to relax yourself?

--Listen to music．

A．over                    B．among                    C．between                 D．through

---What do you often do _______ classes to relax yourself?

---Listen to music.

–What do you often do ____ classes to relax yourself?

–Listen to music.

---What do you often do _______ classes to relax yourself?
---Listen to music.