[单选题]
The reason the positiofnl(:. nx+bow4k0hgt 6 vl1uuj 61cwv mqxk i1h j*q;.my/gms2*zh3mn of a particle cannot be specified with infinite precisio1i/hm*zmcq6 1h;kgmm . 3 vx*jsqjy2wn is the
A. exclusion principle.
B. uncertainty principle.
C. photoelectric effect.
D. principle of relativity.
