A．People among the 60 to 70 age group are more lonely and more sick than among the 50 to 60 age group.
B．There are more mental illnesses among 60 to 70 age group than among the 50 to 60 age group.
C．The 60 to 70 age group and the 50 to 60 age group are in nearly the same mental and physical state.
D．Both groups are lonely and sick.