[单选题]
An n-type semiconduc7,dwd z+3rvaos)my 21dh w(k,asb(yjt p13 tjycq*s)5ay8:u ce jnd/wor 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
