Bismuth ${ } _ { 83 } ^ { 212 } \mathrm { Bi }$

Multiple Choice

Bismuth ${ } _ { 83 } ^ { 212 } \mathrm { Bi }$ is known to be radioactive. The stability of ${ } _ { 83 } ^ { 212 } \mathrm { Bi }$ with respect to alpha, beta-plus and beta-minus decay is to be determined. The following atomic masses are known:
$\begin{array} { l l } { } _ { 2 } ^ { 4 } \mathrm { He } : & 4.002603 \mathrm { u } \\ { } ^ { 208 } \mathrm { TI } : & 207.981998 \\ { } ^ { 212 } \mathrm {~Pb} : & 211.991871 \\ { } _ { 82 } ^ { 212 } \mathrm { Bi } : & 211.991255 \\ { } _ { 83 } ^ { 212 } \mathrm { Po } : & 211.988842 \\ { } ^ { 84 } & \\ \text { The } { } _ { 83 } ^ { 212 } \text { Bi nucleus is } \end{array}$

A) subject to alpha decay only.
B) subject to alpha or beta-minus decay, but not beta-plus decay.
C) subject to alpha or beta-plus decay, but not beta-minus decay.
D) subject to beta-minus decay only.
E) subject to beta-plus decay only.