[单选题]
10.46: For the following n fzisrip+ 5x2ab g8.+ :iwyus+u/e: ab3*zoay(:py08ts1byxk jx bd c4(zeu 2aclear reaction, what is the unknown labeled by X?
$_{11}^{22}Na + X → $_{10}{22}Ne$ +$v_e$
A. A proton
B. An electron
C. A neutron
D. An alpha particle
E. A positron
