Which one of the following nuclear reactions is NOT possible?

The following laws hold true in any reaction
1) Conservation of mass (nucleons)
2) conservation of charge
Checking for all the reactions:

$\sum A_{\text{products }}=\sum A_{\text{reactants }}$

For reaction: ${}_5{}^{11}\mathrm{Be} + {}_1{}^1\mathrm{H} \to {}_4{}^9\mathrm{Be} + {}_2{}^4\mathrm{He}$,

mass numbers of reactants is not equal to mass number of products.

i.e. 11 + 1 ≠ 9 + 4

Hence, this reaction is not possible as mass number is not conserved.