听一段材料，回答下面几个小题。

A．Those who often sent text messages.

B．Those who suffered from heart disease.

C．Those who did no physical exercise.

D．whose who were unmarried

A．They responded more slowly than usual.

B．They sent more messages.

C．They typed 10 percent faster on average.

D．They edited more passages.

A．Why chemical therapy works.

B．Why marriage helps fight cant

C．How unmarried people survive

D．How cancer is detected after marriage.