[单选题]
An electron has an initialwed dqk,r*0 g0 veloj8hbgq6 o3i,s22f ogacity to the south but is observed to curve upward as the result of a magnetic field. Thfggh6oq2s3 2i8, aj obe direction of the magnetic field is
A. to the west.
B. to the east.
C. upward.
D. downward.