Both Sally and Sam receive a 10% raise in a single year. Sally increases her demand for ground beef whereas Sam decreases his demand for ground beef.

A、Thisisimpossible.;
B、ThisisonlypossibleifSallyconsidersgroundbeefaninferiorgood,andSamviewsitasanormalgood.;
C、ThisisonlypossibleifSallyhaslowerincomethanSam.;
D、ThisisonlypossibleifSallyconsidersgroundbeefanormalgoodandSamviewsitasaninferiorgood.