[单选题]
An n-type semiconduc fdpogh+s /3*yv ax(4fta qjjf2 r9gl5h- jqxo c5686ukor is produced by
A. doping the host crystal with donor impurities.
B. doping the host crystal with accepter impurities.
C. pure crystals of germanium.
D. none of the given answers
