Phương trình nào sau đây là phản ứng phân hạch?

\(_9^{19}{\rm{F}} + _1^1{\rm{H}} \to _8^{16}{\rm{O}} + _2^4{\rm{He}}\)

\(_{84}^{210}{\rm{Po}} \to _2^4\alpha + _{82}^{206}{\rm{Pb}}\)

\(_1^2{\rm{H}} + _1^2{\rm{H}} \to _2^3{\rm{He}} + _0^1{\rm{n}}\)

\(_{92}^{235}{\rm{U}} + {\rm{n}} \to _{42}^{85}{\rm{Mo}} + _{57}^{139}{\rm{La}} + 2{\rm{n}} + 7{\beta ^ - }\)