Questions 11 to 18 are based on the conversation you have just heard.

A．Music they like can relieve depression but distract attention.
B．Music they like can reduce stress and improve concentration.
C．Classical music and rock-and-roll increase their heart rate and expand the breathing.
D．Wearing headphones can help concentrate when they are performing operations.

A．It changes the body’s metabolism through rapid weight gain.
B．It tricks the body into responding as if it were in a different time zone.
C．It promotes increased alertness by adding snacks to the diet.
D．It builds resistance to illness by increasing intake of vitamins.