What Happens to the Mass Number and the Atomic Number

What happens to the mass number and the atomic number of an element when it emits gamma radiation?

A) The mass number and atomic numbers remain unchanged.
B) The mass number remains unchanged while the atomic number decreases by one.
C) The mass number decreases by four and the atomic number decreases by two.
D) The mass number remains unchanged while the atomic number increases by one.
E) The mass number increases by four and the atomic number increases by two.