A Radioactive Isotope Decays by α Emission Followed by Two

Multiple Choice

A radioactive isotope decays by α emission followed by two β emissions.What is the change in the mass number and atomic number of the original isotope?

A) The mass number decreases by 4 and the atomic number is unchanged.
B) The mass number increases by 4 and the atomic number increases by 2.
C) The mass number increases by 4 and the atomic number increases by 4.
D) The mass number decreases by 2 and the atomic number decreases by 2.
E) none of the above