Answer
B
Work Step by Step
The atomic weight is the weighted average of the isotope's weights, weighted by their abundances. So for the unknown atom X:
The sum of their abundances must be normalized: $14\%+24.1\%+22.1\%+52.4\%=112.6\%$
$w=(203.94\times0.14+205.97\times0.241+206.98\times0.221+207.98\times0.524)\times\frac1{1.126}$
$w=206.84u$
Which is closer to Pb (207.2u).