[单选题]
A simple junction transistor con2oz 2qbm5u: ha))h pree3mn -psists of three semiconductor pzzi-cl ;2t:x3 yu-ztsections consistingc2;-zyl3z:xti z t u-p of
A. pnp semiconductors.
B. npn semiconductors.
C. either pnp or npn semiconductors.
D. none of the given answers
