[单选题]
An n-type semiconductoznr-wmw(gn l8v *u aifyr.9q9tep 47x/g- d+nr is 7b : kvlk2re4r5 h6e bx;phhpj -ssw)k421omyproduced 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
