[单选题]
An electron has an initial velocity to the soup 63ptscde7 +g0;5gqm)xyb ot th but is ob obv*u 96evh1jserved to curve upward as the 6*vo 9b1euh jvresult of a magnetic field. The direction of the magnetic field is
A. to the west.
B. to the east.
C. upward.
D. downward.
