An experimenter wants to separate silver atoms in a Stern-Gerlach experiment by at least 1 cm (a large separation) as they exit the magnetic field. To heat the silver, she has an oven that can reach 1000°C and needs to order a suitable magnet. What should be the magnet specifications? ( )
A．57 T·m
B．39 T·m
C．75 T·m
D．24 T·m