[单选题]
The part of an electpqsh-om9u5usaeg .- tp09o2m ron 0-imnrva4x,sg9* zzbay* p- y microscope that plays the same role as the lenses do in an optical microscope*x*9i paay-zmbng z4s, 0-yrv is
A. the vacuum chamber.
B. the coils.
C. the cathode.
D. the deflector plates.
