______ some flowers contain more nectar than others, how does a honeybee worker, faced with a patch of flowers containing variable amounts of nectar, decide when to stop collecting

A．from
B．to
C．out of
D．on

A．The raid had been photographed by hidden cameras.
B．Some watchman had seen the raid.
C．The bank teller proved that Joe was the robber.
D．Some monitors had been installed nearby.