Ans:(A)
$$
\begin{aligned}
&{ }_{9}^{\mathrm{F}^{18}} \rightarrow{ }_{\mathrm{x}} \mathrm{E}^{\mathrm{y}}+{ }_{+1} \mathrm{e}^{0} \\
&\mathrm{x}=8, \mathrm{y}=18, \therefore \mathrm{E}^{\mathrm{y}}={ }_{8} \mathrm{O}^{18} \\
&\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}^{18}
\end{aligned}
$$