A lot of people have tried, but ______ have succeeded.

A．Little they realize
B．They little do realize
C．Little realize do they
D．Little do they realize

A．medical decisions for old people should be left to the doctors
B．old people can enjoy a happy life only if they are very rich
C．the opinion that we should try every means possible to save old people is doubtful
D．it is always morally right to treat old people and push off death