Q18. In a hypothetical fission reaction ${ } _ { 92 } X ^ { 236 } \rightarrow { } _ { 56 } Y ^ { 141 } + { } _ { 36 } Z ^ { 92 } + 3 R$ The identity of emitted particles $( \mathrm { R } )$ is :\\
(1) Electron\\
(2) Neutron\\
(3) $\gamma$-radiations\\
(4) Proton