The Nuclide Th Is Radioactive $\alpha$ And $\beta$ -Particle Emissions Occurs,taking the Atom Through Many Transformations to End

Multiple Choice

The nuclide Th is radioactive.When one of these atoms decays,a series of $\alpha$ and $\beta$ -particle emissions occurs,taking the atom through many transformations to end up as an atom of Pb.How many $\alpha$ particles are emitted in converting Th into Pb?

A) 6
B) 8
C) 2
D) 214
E) 4