Consider the Following Decay Series Which Type of Nuclear Process Occurs in Steps a and \mathrm{~Pb}

Consider the following decay series: ${ }_{84}^{218} \mathrm{Po} \xrightarrow{\mathrm{a}}{ }_{82}^{214} \mathrm{~Pb} \xrightarrow{\mathrm{~b}}{ }_{83}^{214} \mathrm{Bi} \xrightarrow{\mathrm{c}}{ }_{84}^{214} \mathrm{Po} \xrightarrow{\mathrm{~d}}{ }_{82}^{210} \mathrm{~Pb}$ Which type of nuclear process occurs in steps a and b, respectively

A) aemission, a emission
B) aemission, b emission
C) bemission, positron emission
D) bemission, a emission
E) positron emission, b emission