[单选题]
10.46: For the following nuijls fnh5 m-,8e17a muclear ea*kshr bip9,52u; l5*ucu d.s2a zboreaction, 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
