For alpha emission:

mass number decreases by 4; 218 - 4 = 214

atomic number decreases by 2; 84 - 2 = 82

Isotope is ₈₂²¹⁴Pb

For Beta minus decay:

mass number is unchanged

atomic number increases by 1:   82+1=83

Isotope is  ₈₃²¹⁴Pb

Answer is B

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