Radioactivity: the Stability of C with Respect to Alpha

Radioactivity: The stability of C with respect to alpha, β⁺, and β^- decay is to be determined. Do not consider the possibility of decay by electron capture. The following atomic masses are known: He: 4.002603 u Be: 7.016928 u B: 11.009305 u C: 11.011433 u N: 11.026742 u The C nuclide is

A) not subject to alpha, β⁺, or β^- decay.
B) subject to alpha decay only.
C) subject to β⁺ decay only.
D) subject to β^- decay only.
E) subject to β⁺ or β^- decay, but not to alpha decay.