Which word best describes Professor Hall's relationship with his students

A．Giving a lecture.
B．Discussing political science.
C．Working on a science problem.
D．Reading books in a library.

A．They don't like people to drop in without a previous invitation.
B．They never send an elderly relative to an old persons' home.
C．They like their home and family better than their garden and pets.
D．They think it the family's duty to look after an elderly parent.