In the Nuclear Reaction $\begin{array} { c } 16 \\8\end{array}$ O

In the nuclear reaction $\begin{array} { c } 16 \\8\end{array}$ O + ${}^{4}_{2}$ He → X + ${}^{19}_{10}$ Ne,what is X?

A) proton
B) neutron
C) ²H
D) ³H
E) alpha particle