[单选题]
A distinctive feature wu yv3r oov06e.s5oy5 of(, vrkqfuu, l7;x lse0dxsm ,9 quarks is that they
A. have zero rest mass.
B. have zero charge.
C. have fractional electric charge.
D. are always observed singly, since they do not readily interact with other particles.
Post time 2024-1-22 02:15:01