147712
Assertion: ${ }_{\mathrm{z}} \mathrm{X}^{\mathrm{A}}$ undergoes $2 \alpha$-decays, $2 \beta$ decays and $2 \gamma$-decays and the daughter product is $\mathrm{z}-2 \mathrm{X}^{\mathrm{A}-8}$.
Reason: In $\alpha$-decays the mass number decreases by 4 and atomic number decreases by 2 . In $2 \beta$-decays the mass number remains unchanged, but atomic number increases by 1 only.
147712
Assertion: ${ }_{\mathrm{z}} \mathrm{X}^{\mathrm{A}}$ undergoes $2 \alpha$-decays, $2 \beta$ decays and $2 \gamma$-decays and the daughter product is $\mathrm{z}-2 \mathrm{X}^{\mathrm{A}-8}$.
Reason: In $\alpha$-decays the mass number decreases by 4 and atomic number decreases by 2 . In $2 \beta$-decays the mass number remains unchanged, but atomic number increases by 1 only.
147712
Assertion: ${ }_{\mathrm{z}} \mathrm{X}^{\mathrm{A}}$ undergoes $2 \alpha$-decays, $2 \beta$ decays and $2 \gamma$-decays and the daughter product is $\mathrm{z}-2 \mathrm{X}^{\mathrm{A}-8}$.
Reason: In $\alpha$-decays the mass number decreases by 4 and atomic number decreases by 2 . In $2 \beta$-decays the mass number remains unchanged, but atomic number increases by 1 only.
147712
Assertion: ${ }_{\mathrm{z}} \mathrm{X}^{\mathrm{A}}$ undergoes $2 \alpha$-decays, $2 \beta$ decays and $2 \gamma$-decays and the daughter product is $\mathrm{z}-2 \mathrm{X}^{\mathrm{A}-8}$.
Reason: In $\alpha$-decays the mass number decreases by 4 and atomic number decreases by 2 . In $2 \beta$-decays the mass number remains unchanged, but atomic number increases by 1 only.
147712
Assertion: ${ }_{\mathrm{z}} \mathrm{X}^{\mathrm{A}}$ undergoes $2 \alpha$-decays, $2 \beta$ decays and $2 \gamma$-decays and the daughter product is $\mathrm{z}-2 \mathrm{X}^{\mathrm{A}-8}$.
Reason: In $\alpha$-decays the mass number decreases by 4 and atomic number decreases by 2 . In $2 \beta$-decays the mass number remains unchanged, but atomic number increases by 1 only.