When A $\beta ^ { + }$ Particle Is Emitted from an Unstable Nucleus, the Atomic Number

When a $\beta ^ { + }$ particle is emitted from an unstable nucleus, the atomic number of the nucleus

A) decreases by 1 .
B) decreases by $2 .$
C) increases by 1 .
D) increases by 2 .
E) does not change.