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

(1) Mass number increases by four and atomic number increases by two.

(2) Mass number decreases by four and atomic number decreases by two.

(3) Mass number and atomic number remain unchanged.

(4) Mass number remains unchanged while atomic number decreases by one.

(1) Mass number increases by four and atomic number increases by two.

(2) Mass number decreases by four and atomic number decreases by two.

(3) Mass number and atomic number remain unchanged.

(4) Mass number remains unchanged while atomic number decreases by one.