Answer:
A. A neutron transforms into a proton and an electron.
Explanation:
Yes, this is what happens in β decay.
[tex]_{0}^{1}\text{n} \rightarrow _{1}^{1}\text{H} + _{-1}^{0}\text{e}[/tex]
The proton stays in the nucleus and increases the atomic number by one, and the electron is ejected from the nucleus.
B is wrong. This is impossible because charge is not conserved. You can’t convert a positive particle into a negative particle.
C is wrong. Again, this is impossible because charge is not conserved.
D is wrong. Charge is conserved, but this is the process of electron capture.
