If a Nucleus Undergoes Alpha Particle Emission

Multiple Choice

If a nucleus undergoes alpha particle emission:

A) its atomic number decreases by two and its mass number decreases by four.
B) its atomic number decreases by one and its mass number is unchanged
C) its atomic number increases by two and its mass number is unchanged.
D) its atomic number decreases by two and its mass number is unchanged.
E) its atomic number is unchanged and its mass number decreases by one.